Sorry for the slow response.I was away from my computer
and my phone is dumb.
Mine is closer to what is called an elite Powervest.
I think Dave Miller uses the elite powervest as a training aid
from time to time.
The backplate is shorter with no waist belt.
A 2" wide slot is cut about halfway up from the bottom to
allow the 2 vest straps to secure the vest well enough
to hold it in position.
I use a heat gun to better fit my shoulders
to the backplate.I just heat and form and see how it fits.
Without the waist belt this is a lot less critical.
I am not brave enough to let my wife lay any molten plastic on my back.
If your backplate cracks in the shoulder area and you have some old backplate material around you can laminate a patch
over the cracked area as a temporary fix while waiting for
a new backplate.I used some fasteners from the hardware
store (that are like rivets but they are threaded)
to attach the patch.
This helps keep you skiing.
None of these mods are factory approved
and my warranty is voided.
A year or two ago I was at a Cottonwood tournament
that Horton was at and he looked at me wearing this vest,shook his head,and walked away.