I have tried a lot of bags of different sizes, fill type and fill quantity made by all of the usual subjects.
My hands aren't small but not large either. I have never found a bag that could be used in the way that Frank and Marc teach in their classes. When I first took their class last year, I struggled with being able to build a solid rear foundation. I really can't emphasize how important it is and unfortunately no degree of classroom instruction can show you the aftermath of poor rear back foundation. A minute difference in the rear can amount to a significant shift in POI even at 100 yards. Some people believe that they can overcome it by contorting the bag so that it allows proper shot alignment but it is a fool's folly. You may get it right some of the time but you will never be consistent and in this game consistency is king.
Once you realize and SEE what a properly sized bag with the right amount of structure that can be grasped and molded properly will do for your consistency, you will be a believer. The design is utilitarian but simplicity is the key to its ability to deliver results. This, of course, assumes that you have learned and committed to muscle memory the other requisite steps for firing a good shot CONSISTENTLY.
This is a cheap way to improve your end game...no other way to say it. If you're shooting prone, you are missing out by not trying this bag. The cost is laughably cheap.
Just my 2 cents