So yes you can take your shoes off (I did). Just rode Thursday... I'm a 6'5 guy, 330+ lbs and 53+ inch waist... Size 14 shoes, 20" calves, very long legs (I can wear a 36" inseam).
With shoes on, had a bit of difficulty getting my heels far enough forward... Probably would have been ok but wanted to be safe. With shoes off, was easily able to curl toes up to give me a couple extra inches.
Regarding the rest, I tried test seat and did what everyone else tries first (pressing "forward" to try to "force" yourself tighter into the torso restraint)... This has the OPPOSITE effect desired as it actually shifts your lower back further backwards the harder you squeeze! I was just a *sliver* in the red using this approach. Don't do this.
As you start to straddle the thing, wedge your legs in as far forward / tight as you can. Shoes off for huge feet (just stick them in the storage bin, easy! CM had no issues with this.)
Then firmly grab the handlebars with both hands and use them to pull in snug and stretch up as tall as you can in the seat - arch back as folks have described - stretch up as far as you can and hold that position until the restraints engage!!
When I did it this way, immediately made it into the green zone in test seat... And on the ride itself, CM did not even have to push! I was shocked, asked "am I good?!?" To which the answer was simply "yep!"
Hope this helps, I appreciated the trip reports I read before my trip (was worried I wouldn't make it)... As a gorilla-sized giant guy it should give you all some comfort that it's more about technique... I found it to be perfectly comfortable and agree 100% the best ride at WDW... Have to ride to believe.
Take care all and good luck -
Scott