Would you say there's an even mix of shorter and longer pages, or more shorter than longer? By setting a sechedual you can also work ahead of it when you feel a rush of motivation...I haven't worked on undersaga for a week now, and I still have six finished pages to put up. You could finish this page in a week, then work on the next one that maybe takes a week, then you have a months worth of posts done in half that time, so you have extra time to work on the long ones.
I appreciate wanting to have impact breaks in the action, I do the same, though I have to to manage my breaks to work within my page size. This works out to arranging each page to land in a mini cliff hanger or resolution. For example, one page ended with a character starting to go into a complete emotional breakdown for the first time since a massive loss, and the next page ends with the conclusion of that breakdown, and the NEXT page ends with the character processing all the destruction they caused. Its interesting to have a physical limit on how big my pages can be, forcing me to be creative, shift things around create extra panels or take them away, so that there's a good stopping point on the last panel every time. It does often result in 'garbage' panels though...extreme closeups of like...the back of a characters head, or a hand, just to not have the same poses in an extra panel I had to throw in to accommodate some important dialogue that didn't fit right in other panels.