Cross-Figure Genesis 3 is a program that allows you to use Genesis 3 Female hair and clothing on Genesis 3 Male and vice versa without using AutoFit. There are some extra steps using it with Genesis 8, but you don't have to be able to use a modeling program (unless you want to make a better ID morph after you're done, but we'll get to that).
Genesis 8 Male and Female
Instructions G8F to G8M:
Load Genesis 8 Female into the scene.
Load a piece of clothing or hair onto Genesis 8 Female that you wish to convert.
Go to the Parameters tab. If you do not have one, you can create one by right-clicking near your existing tabs and finding it in the list.
Click on the tiny button at top left of this tab (or top right if you keep it on the right) and make sure Show Hidden is checked.
Now in the Parameters with Genesis 8 Female selected, go to Hidden/Clones. Dial the clone for Genesis 8 Male to 100%. Genesis 8 Female suddenly turns into her male counterpart, and the clothes pick up the morph without triggering AutoFit.
Select the clothing. You should see the CloneGenesis8Male morph in the clothing now.
Click on the gear icon to the top right of the morph name and choose "parameters."
Now you should see a dialog pop up that contains some information about the morph, including its name. Change the name and label both to XID_Genesis8Male instead of CloneGenesis8Male.
With the clothing still selected, go to the Scripts folder in your Content Library. Under Utilities, you should find the Cross-Figure Setup button. Double-click it.
It should run and tell you that setup is completed. Click OK.
Now there should be three morphs in your clothing under hidden, two that start with XID and one that starts with FID.
Unconform the clothing from Genesis 8 Female. Delete her, but leave the clothing in the scene.
Load Genesis 8 Male. Do not conform to him yet. Just dial the XID_Genesis8Male morph to 100% in the unconformed clothing.
In the Scene Tab, click on Genesis 8 Male. Hold down CTRL in Windows (sorry, I do not know the Mac equivalent) and click on the clothing. It's important that it be in this order, figure, THEN clothing.
Find the little button at top right of the Scene Tab and click on it. Find Edit--Rigging--Transfer Rigging (Figure Space) and click on it.
This transfers rigging to the clothing for just bones with the same names (it won't affect custom skirt or sleeve bones, which is good). We want that change to apply only to the XID_Genesis8Male morph, so we'll ERC Freeze it.
Right-click the XID_Genesis8Male morph in Parameters Tab. If Edit Mode is not checked, check it.
Below that, click on ERC Freeze.
Now you are ready to save the three morphs to the library, the FID morph and the two XID morphs.
Save using File--Save As--Support Asset--Morph Assets.
It doesn't really matter what you put in the box that comes up as long as you expand out the list and check those three morphs to make sure they are saved. I have a separate directory for the top dropdown to save extra morphs like this to, but that is up to you.
When you have put a check by all three morphs, click Accept.
Now you should be able to delete the clothing from the scene. When you select Genesis 8 Male and load the clothing again, it will conform to him correctly without AutoFit.
Bonus For Modelers (Text tutorial only): Better XID Morph
Now, if you use this on a dress or robe or long shirt or coat, you will note an ugly triangular artifact in the crotch area. If you would like to fix this or other visual problems with the XID_Genesis8Male morph, and you already know how to use a modeling software such as Blender, Hexagon, Modo, etc., you can fix it in your modeling software.
Hide everything in the scene but the clothing. In Parameters, make sure the clothing is set to its Base resolution and 0 subdivision.
Dial the XID_Genesis8Male (or female as the case may be) morph to 100%.
File--Export. Choose obj.
Import the obj you exported to your modeling software (I use Blender). Make sure your import settings preserve vertex order - Blender by default does not!
Now you can smooth out the clothing with sculpt brushes or direct manipulation of the vertices. If you don't already have a file saved with Genesis 8 Male (or Female) in it, you can repeat the obj export with everything hidden but the zeroed Genesis 8, and import that to work with.
When you are satisfied with how your morph looks, export from your modeling software to obj again. Again, make sure vertex order is retained. You have to check a box for this in Blender for sure, but I don't now about other softwares.
Now, in Daz Studio, select the clothing and start Morph Loader Pro. Its icon looks like a flexing arm.
Click on Choose Files and navigate to your XID morph obj file. It needs to still have the name XID_Genesis8Male. If it does not, rename it now.
After you select that, go down to the Morph Loader Pro setting that says OverWrite Existing. To the right of it, it says Make Unique. Right click on Make Unique and change it to Deltas Only.
Now click Accept.
If it says geometry does not match, you may have made one of these errors:
You forgot to hide some other geometry before export, such as the eyelashes of Genesis 8 Female. Delete this geometry from your modeling software and re-export; it may work.
You forgot to set the clothing to Base resolution and 0 subdivisions. If it's this I'm afraid you must start over.
You forgot to import or export from your modeling software with vertex order retained. You may have to redo it with this one, too, depending on which step you forgot.
If you did not get a geometry error:
You should now see your new and improved XID morph when the clothing is conformed. Save it to the library again using File--Save As--Support Asset--Morph Assets. Now when you delete and reload the clothing, your fixed version of the morph should still be there!