18" tire options for 2500 with 3" ReadyLift? South Texas washboard roads...

2022 2500 Gen 5 diesel 4x4. I just had a ReadyLift 3" kit installed...new progressive coils and Falcon shocks. My oilfield job has me driving on ranch roads in south Texas. I drive about 50 miles a day at 25mph(speed limit) on roads which are either washboard and/or pot-hole nightmares. Imagine a road with thousands of softball sized rocks half-buried and spaced 6 inches apart for about 10 miles. After 6 months of beating the factory suspension, and myself, to death I decided to do what I could within my budget.
Anyway, my current tires, Nitto Ridge Grappler LT295/70R 18, are going to be replaced soon and I was looking for input on if I can get a little more rubber on the factory 18" rims to help improve the ride. ReadyLift states max is 35" and my current Nitto's are 34".
Am I limited to 35", or is there room for another inch or so? If not, no big deal...I just want to make the most any additional room I may have to work with now. Main reason I'm asking is because my current tires look a little small to me now that the truck is lifted a few inches.

Thanks.

35’s would fit without a doubt. 37’s should even fit, probably get minor rubbing on the sway bar and or radius arms at full lock, but nothing that causes any issue. There are a few 37x11.5 offerings out there now that would be a great fit. The ridge grappler is one of them.

Out of curiosity, how does the suspension handle your driving compared to the oem?