Klein Budget for a Klein bicycle / gravel's biggest chopper

I recently bought an orange p7 which has naturally turned into my do everything gravel bike, + moving house demands that I cut down on the number of bikes I have unforunately.

For 700c i was running 43's but this ultimately depends on how low the brake bridge in the rear stays is, I could probably squeeze in a 45 but for the sake of mud clearance I'd stick with 43's

This is also going to vary depending on what 26" MTB you have

As for 26", to be on the safe side I'd go no larger than 2.2, but it depends on how big the tried is, on my orange I bought a pair of 2.25 schwalbe table tops that fit a treat with mudguards