Here's a few pics to help you decide.
a) First pic shows the arial view (hee hee) of how it keeps things organized for me in my Speedy 30. I can easily access the items I constantly use - my wallets, agenda, cell, keys....
b) Next shows the distance between the PT 26 and the top of the bag (Damier 30 still)
c) Next up is the organization in the Monty GM...
d) You can see how in the Monty GM the fit is looser and better...
e) And a group shot to get a bit of perspective on the sizes...
The 30 is a tighter fit, but I like it for how it helps keeps things organized; keep in mind I do not pull it out of the bag - it's more of a purse organizer in there. I also like how the PT 26 gives it some structure but when I hold it there's still some sag (I love the sag)...
In the Monty GM the fit is much roomier and I can still keep the organization that I like (as I don't like searching for what I need, but I LOVE big bags)....
On a side note the PT 26 does make a FABULOUS clutch! I used it as one not too long ago for travel (was really helpful as the eve clutch I had brought was too small for everything I wanted to carry!).
Hope this helps!!!