I have the Salomon Pro Model and the yellow and black Fischer MX from a few years back. Both are size 28.5. My New Balance running shoes are 11.5-B. My natural stance is toes out. Yes I think the Pro Model is a 98 last - 95 flex and I think the Fischer is a 105 flex in this model. I've seen the last listed as 100 and 102 on the Fischer's. When I bought them the ad said the last 100 on the ones I bought and 102 on the 95 flex. The box and literature did not say and literature I read later was confusing so I don't really know. Reviewers say the Fischer boots fit better overall than the MX.
My Fischer's are larger (overall more volume), stiffer, harder to put on and take off and warmer. Both pair have heel lifts to help set the top of my ankle to the front of the boot. I added a bontex (?) spacer under the boot liner in the Fischer to take up the extra space. I've experimented with the rubber wedges both under my heel and forefoot. I'd need to take out the liner and look inside the boot to see what was stuck where today. I do tend to tinker with my boots!e
I've tried Intuition liners in both boots and now use a conventional tongue model Intuition in the Salomon's and went back to the stock liner for the Fischer's. The Power Wrap Intuitions in the Fischer's were stiffer than I wanted at the time. If I get to looking for something stiffer I'll reinstall the Intuitions.
The Salomon's have been canted 1.5 (inside higher) on each side and had two places punched to give a little more toe room. They start with a more narrow shell and then I added a liner with a little more volume than the stock liner so naturally they fit snug.The Salomon's have SuperFeet insoles and the Fischer's have Surefoot custom insoles that are a little thicker than usual and have a little tilt built into them. The boots have different sole lengths so I use them to ski different skis. I really can't tell much difference other than the stiffness but remember the Salomon's have been canted and the Fischer's are flat but the toe out stance provides some of the same adjustment as canting. Both are comfortable so I'm happy.
At some point I'll probably get curious and get the Fischer's canted to see if that makes much difference.
Last year I bought some slightly used Full Tilts to see if I like that setup and I could not make it work for me. Same 28.5 shell but not enough toe room for my foot. Probably an anatomical thing. Anyway I always wanted to try some and now I've got that out of my system for a while.
As to flex ratings, I do not think they are uniform across brands but they are similar. It's also hard to judge in the store. Evidently my boots use different plastics becasue the Fischers are more temperature sensitive. If it's really cold they get noticeably stiffer. The Salomon's seem more uniform over a broader temperature range. In general a 100 is not a stiff boot. Plus there are other factors about a boot's design that may impact ski control more than stiffness.