That is a beautiful example of a monoshock conversion, it looks retro and modern at the same time and you have the skill and knowledge to do it properly but generally, I prefer a two shock bike to remain so. You can get some very good twin shocks now and I always wonder if the original part of the frame can withstand the extra g-forces that a modern swingarm and wide tire (and also a modern front end) can allow without extra bracing. I think I first read in Tony Foale's writing about how even improper bracing can lead to a flexing frame or even lead to the frame braking. Having owned an H2, GT750 and a few T500's and a GT500, I am pretty familiar with frame flexing. On my H2 I had the frame braced the same way that the racers did with the Z1's, upgraded the suspension and reduced the weight and for my abilities, it handled very well. But I digress.
I agree with lots of the previous comments but would add stainless steel bolts in an aluminum engine without using anti-seize (I have done this), I have also used low bars with stock pegs because I did not have the dough to buy rear sets, swing arm mounted license plates, lowered front ends, those dreadful Goodyear tires, sawed off exhausts and a personal pet peave, ugly homemade seats. Those ugly seats can ruin an otherwise nice looking bike.
Brian