It kind of depends on your goal. Here are a few points to consider.
Like you,
@Pacific Wheel and I were talking about in the other thread. I thought that I had seen aftermarket flares that were wider than stock. Then you could just run spacers or offset wheels and the 35s would still look ok.
Most run wider fenders due to mid travel and/or bigger tires. 37s can rip your stock fenders off even with the correct offset wheel due to the wheel opening.
Fenders also have a bigger wheel opening so 35s might look small to some. But you really don't "need" bedsides until you run a wider rear end (giggity). Going mid travel also pushes the wheels towards to front of the truck to give more room for clearance bigger tires from the rear of the fender opening.
Just doing the fenders and not bedsides looks funny to me. Unfinished project. So if you replace fenders and bedsides without a rear end upgrade, run spacers if you mid travel the front.
Getting a wider stance is a big rabbit hole to go down. Seems never ending at times. So have a honest conversation with yourself on what your goal is. No reason to go mid travel if you just want the look. If that's the case I would just start with wider flares and a different offset wheel. And if that isn't wide enough, add spacers. Still not the right look? Go mid travel.
Here is my current set up. Camera angle was more for the lights but I can get a different angle for you when I go home on Friday. I just have a zero offset wheel. Fenders, flares and the track width are stock. 17x9 zero offset wheel with 12.5 37s.
I don't have a square head on picture when I had the 20x10s on but this one shows a wider width then the other side profile pictures I have. They were also zero offset with 12.5 37s.
You can add spacers to your current wheels and see if you are happy with that look. If so order a wheel you like to accommodate that offset. Just remember, that if you go too wide you will have stock fender limits.