It just depends on how much shoulder you like/need/can stand.
235 is perfectly acceptable on 8” rims.
Some tyres are going to have a bigger shoulder than others eg ad08r is on the larger size.
Read an faq:
https://legacygt.com/forums/showthread. ... -4426.htmlCalculate your proposed & current fitment at eg willtheyfit com...
Imho, your proposed specs will require some guard work pending final ride height and camber settings plus tyre shoulder.
Ideally you’ll do the guard roll etc before using the tyres, if they rub, your new tyres will get cut on the shoulders.