That valve is a work of art! Gorgeous..
I am sure vintage rules will not allow anything lower profile than 60 series for vintage racing, though some US sanctioning bodies such as HSR allow more latitude.
I used to use 205/50/15 Yokohama 032R in Solo 1 but thay did not really suit the irs very well, lots of grip but very sudden breakaway. Trailing throttle oversteer was the quick way into the corner.
I used a TR6 sway bar on the front, none on the rear, this helped reduce wheelspin out of second gear corners. My brake pads were Rewpco semi metallic (from Australia), but overall my car was not nearly as highly developed as yours.
Nice to see the details, thanks Chris!