Shoulder Belt Device

[ProTouring442]

Ok guys, I have an idea on which I need advice. My 72 442 is a convertible, so installing shoulder belt (the three-point stock kind) is problematic. The shoulder mount needs to be higher than the 1/4 panel. This would look rather unsightly, but I think it really needs to be done for safety's sake. So my thought is to make a motorized stand that will rise to the correct hieght when the key is on, but lower to the interior panel when the key is off. I figure some good square structual tubing and a linear actuator should do the trick, but I am unsure of the size needed to be useful in the event of a need for the shoulder belt. I am turning to the board because most of you are way smarter than I, and collectively...

What do you think?

Thanks!
Bill
72 442 "Inamorata"