[Buzz]

Very interesting project, Roger! I'll leave the subframe suggestions to others with relevant expertise, and my suggestion for the mounting points would be for the front - try adapting the same front (windshield) mounting system used on most manufacturer's soft tops. The rigidity of the aluminum top would negate the need for the center pins to slide into the windshield frame so a continuous channel with a neoprene weather seal using OEM latches/brackets at either end should work. For the body attachments, it looks like two rear threaded posts could insert into ferruled holes in the rear deck. Access through the trunk should allow you to tighten them down with wing nuts. Two more threaded posts could be placed to mount through ferrules in the body just behind each door and the nuts could be tightened from the cockpit. If the danger of paint damage during installation/removal is too great with fixed posts sticking out of the bottom of the hard top, try using threaded inserts in the body and bolting the top down from inside the cockpit once it is in place. You could also be real creative and adapt a C4 Corvette-type cable release attachment for the rear pins.
I am curious about the profile of your top. Could you post a pic showing the car and bucks from the side?