"I have a set of Wirth German progressive fork springs and with those fitted and the good yss shocks on it, there's a good chance of a rewarding satisfying ride."
I feel, when riding them in contemporary use, that there was often fuss made of them and Japanese bikes generally of not handling well. Often this by people that had never ridden example of what they were talking about either.
To me the 750 is a very neutral and decently competent chassis. Certainly with rider only it handled well and seemed to be unjustly criticised often by a brit focused press and relayed parrot fashion across folklore type projection.
I didn't have a direct comparison in riding brit bikes at that time, but more recently having ridden example of these, still feels the same. There's no real night and day detrimental characteristics in the Honda. Very high speed, added pillion and perhaps more severe production racing operation I could see bringing more critical appraisal, but likely the same for most road bikes.
Rear shocks, while adequate for solo and legal road riding would be target for extensive pillion work or very high energy and speed situations in changes that could be desirable and one which you've obviously considered here. Girling gas shocks, when contemporary, seemed to go too far towards restricting suspension at least for solo road work, generally being bone hard like that, but more optimum when carrying pillion.
As with most bikes, headstock bearings and swingarm pivot in good condition bring a foundation basis to then choose more freely suspension component.
I've a particular dislike of headstock either with play and any notching of the bottom race, ultimately to affect the steering. Again in contemporary use most in use that I rode with used taper roller headsets (from Dresda shop in Putney

) that were a drop in replacement and very good in their effect.
Tyre sensitivity, was notable in rear getting worn square and starting that way in Avon Road runner at that that time. I used Dunlop Red Arrow or 1st gen Pirelli Phantom with much rounder profile (TT 100 wore too quickly into flat on rear) which worked as good match for the chassis design, that also evolving with decent round profile in original Bridgestone pattern.
Forks, I usually use a lighter damping oil of decent quality to ensure they don't give that heavily damped feel, with "bobbing" over smaller road irregularities. Sounds a good choice to go with a quality progressive spring as you've chosen.
It often frustrates that even now there's the assumption these weren't all that good in handling (that's in general Internet view) when so many of them must have covered literally a combined millions of miles since coming to market. Every big bike race visited in early years had thousands of them parked, both brit and often continental registered.
I was riding a K6 home in early hours of the "great storm" of 1987

after closing a factory and getting staff away as the roof was lifing up and down, a few detour for blocked roads, but remarkable in its stability, even riding on a straight road at about 30 degree lean

Seems like you'll have a very nice riding bike there to me. Always look good with the four pipes too.