It also depends lot of liners you use. When i got Zipfits i realized that i could go one size down without any issues. Later found that also thermos work, you just need to find way how to therm them.
I have this one and by changing angle of stick you can adjust view.
http://store.insta360.com/product/third_person_backpack_mount?from=products_recommended
Been riding bout 2000 days and hit only ones by skier, and that happened day when we two were only two person in resort.
Best advice is learn to look upwards hill after every turn you make. Later when your speed increase you might take look after every second turn.
One could quite easily build from 6mm carbon plate mini raisers with some extra inserts.
That would not cost much. Same applies naturally if there is too short or too long stance options.
180cm
stance 54cm, 1-2cm forward from insert mediumf
front 60deg, rear 55 deg
UPZ with Intec heels, 10cm raise on rear heel
with this stance last 24 years, before that with 44cm
I once cut just 10mm Alu blocks and drilled hole to go to insert in board and another threaded one to install plate. Block was about 10x20x 60 if i recall right, needed 4 of them.