Check out
https://tiresize.com/calculator/ to compare different tire sizes. 265/35 is a bit small. 255/40 is closer to stock.
The vendor where you buy the wheels will probably recommend lug nuts.
I have seen You Tubes on +38 being the "perfect" fit where "perfect" means flush with the fenders. However I have seen posts on this forum from people who were surprised at how +38 actually fit when they got them. Personally if "perfect" mean flush look and that's what you are going for I would go with +45. I think you will find that flush enough. If "perfect" means keeping OEM handling stick with +50 or above.
Going below +45 might require rolling the fenders. Fit is going to vary depending on the actual wheel and the actual tire selected. Tire and wheels are a bit like shoes. One brand size 10 is a 10.5 in another brand.