For me, using a riffle force is tough with Jumbo cards because the cut before the force looks out of place and it hard to get an effective a pinkie break.
A cross cut force works best for Jumbo cards. If you want to do a classic force, it can be done but you need to use a different handling for Jumbo cards (PM me if you want details).
Also check out Mark Wilson's Complete Course for the following forces that work with Jumbo Cards:
10 to 20 Force
Rollover Force
Count Force
Hindu Flash Force (perfect for forcing a different colored back card)
Perfect Card Force
Also the Table Spread Force from Expert Card Technique (which is an amazing force when it works, but should only be used if you have a back-up effect) can be adapted for Jumbo cards.
All that being said, I typically use the Cross Cut Force, Perfect Card Force and Rollover Force with Jumbo Cards. I've also used a variation of the 10 to 20 Force where I don't touch the cards.