Tires for 1998 TM2619

I'm looking to replace the Carlile Tires on the 1998 TM2619 that I purchased last fall with Goodyear Marathons.  My problem is that no one seems to be able to tell me definitively whether I can go with 14" tires or if I need to stay with the 13" that are currently mounted on the trailer.  From a safety standpoint, I can't see putting on 13" Marathons (the 13" tires only are rated up to 1360 1bs and the trailer weights about 25001bs dry).  I would like to move up to ST215/75R14 size tire to increase the weight capacity to 1,8701bs per tire.  I spoke to a couple people at Trailmanor in Tennessee and they both said that most likely I could upgrade to the bigger tires but they were not 100% sure.  I also spoke to a local Goodyear dealers and he said that even if they looked at the trailer, they couldn't be 100% sure the bigger tires would work.

If some of you owners of TM2619's built in the same era could tell me whether you are using 14" tires and the dimensions of your wheel wells, I could determine if the 14" tires would work for me.   I would appreciate any help that you could give me.