On the TL motor front, I reckon it'll have that frame for breakfast, and the RZ sounds a much better option

The vibration from the big v-twin tl motor coupled with the torque output tends to destroy frames and even the stock tl frame was prone to cracking in the odd place due to it.
The tuned xt500 engine thats in my supermoto project was originally housed in a modern CR250 motocrosser with lightweight ally frame, but it was prone to cracking the main front frame loop around the headstock and downtube area etc. The builder added lots of bracing etc but never fully cured the issue, requiring regular inspection/tig attention and a replacement front loop per season, eventually tiring of it hence breaking it and selling me the lovely engine

With the tl motor it'll be a weird tl that probably wont be much of an improvement over a stock one with all the excess hacksawed off, but with the rz shrieking away through expansion chambers itll be like a little historic gp rep... If its not already obvious I think the stroker is the better option, though they must be getting rarer to find decent once even stateside.
Do you have the dimensions of the cbr swinger and forks? Im trying to collate a list of swingarm dimesions for another website Im involved with that involves modifying older jap 4 strokes with more modern running gear...
This is what I have for the hawk if its any help :-
Hawk (shock is direct-mounted to top of swingarm)(shock end is an 'eye')
Length: 545
Pivot width: 235
Pivot diameter (right): 15
Pivot diameter (left): <22
Eccentric outside diameter: 105
Eccentric width: 70 (+3 crenelated 'edge')
Caliper carrier diameter: 75
Caliper carrier width: 14
Brake rotor diameter: 240
Brake rotor mount diameter: 100
Sprocket mount diameter: 165
Wheel drive diameter: 100
Im currently weighing up stuffing a late model z1000r swingarm/190 wheel, and some zx9r-b2 inverted forks, with a zx9r-c2 wheel, a zxr750 top triple, with a zr7 bottom triple, and some random toxico 6 pot calipers I found in the shed into the gpz1100b2 I have. But I need my workshop to have a concrete floor and the lathe/mill set back up before starting that or it'll be another bike in bits in the shed waiting for eternity progress blocked by waiting for some bracket or bush to be turned/milled, like the other 6...