A little left to right mis-balance is going to be no problem with the R250's which are very over built steel ply carcass tires. Put 5 to 10 pounds more inflation than the table for 2600 on each tire or just put them at 80 pounds inflation. With similar weight I run 71 pounds in mine. I ran 65 according to the trailer placard for the first few years on RIBs and notice slight more wear on the outer ribs, so I upped inflation to 71 and they wore evenly. So I run the R250's at the same 71 pounds.
When you run a RIBs or R250s on a 5200 or 6K axle you do not have to worry about to many things except enjoying your trip.
BTW both my Ribs for 6.5 years and now the R250's for two years hold air pressure VERY well, not requiring adding air except every 1-2 years, and that was only because a valve core that needed to be tighten.
To the OP, you will be a happy camper for many years.
Chris