Considering the weight of the 23 trailer, the 15" Michelin LTX (P) 235/75R15 XL tires would carry the weight quite safely. I used them on my 2013 25FB International Serenity with a GVGW of 7,300 pounds. My 15" Michelins had a 2,183 pound load rating on the sidewall. Using the derated capacity for trailer use, four 15" Michelins were rated for (4 x 1985 = 7,940 pounds) on my 25FB.
Under my avatar is the link to images. You can see a takeoff 15" Goodyear Marathon still mounted on a factory 15" aluminum wheel next to the tire captioned above also mounted on a factory 15" aluminum wheel during my tire swap process.
15" Goodyear Marathon diameter is 28.3"
15" Michelin LTX (P) 235/75R15 XL diameter is 28.9"
16" Michelin LT 225/75R16E LTX M/S2 diameter is 29.2"
You might consider the 15" tire size and acquire a set of "used" Airstream aluminum wheels from someone like myself with a Classic 30 (GVW of 10,000 pounds) coming in at the end of January and switching to 16" Michelins to carry the heavier trailer and will have a set of four Aluminum and one steel wheel with just the mileage incurred coming from Jackson Center to the local dealership in Mesa, AZ.
WBCCI Life Member 5123, AIR 70341, 4CU, WD9EMC
TV - 2012 Dodge 2500 4x4 Cummins HO, automatic, Centramatics, Kelderman level ride airbag suspension, bed shell
2014 31' Classic model 30 twin beds, 50 amp service, 900 watt solar system, Centramatics, Dill TPMS, disc brakes, 16" tires & wheels