1.5 to 2 fingers is a good "comfort" fit--as long as it's taken with your toes just brushing the front. Sometimes, when the fitters hand goes in to measure, your foot slides forward and makes this measurement inaccurate. This is one reason some of the best fitters use a dowel and a flashlight.
How do the shell shapes match your foot shape (forefoot width, heel pocket size and shape, etc.)? From what you're writing here, I don't think any of the shells match your foot shape very well.
Also, depending on how the footbed was made, it may or may not be helping matters. Normally, a well-made footbed will help limit fore/aft movement in the boot.
If you lever off your boot cuff to the rear ("sit back"), this will cause your foot to slide forward in virtually any boot (unless you physically can't). This may mean that technique is contributing to your issues (see the ESA
site for information on how to correct that!).
You might consider asking Jeff Bergeron over in his thread. But, if you do, make sure to match his format (given in the first post).