The easy fix is to get one inch spacers for the narrow axle. Spacers are very common in the off-roading world where they put 2 inch or more wide spacers on the vehicle wheels so their big wide tires will fit inside the truck. Should be no problem on a trailer.
Never use wheel spacers on a road trailer/high axle loads. Probably a non issue on a off road trailer that may never see lots of highway speed and high axle loading. BTDT and saw the results from other O/O's.
Trailer axles/wheels/hubs places all the weight between the inner and outer axle bearings unlike automotive wheel/hubs.
Also trailer axles/wheels/hubs have a whole lot more side stresses than a truck/car/suv.
The company I sub'd for had several GN flatdeck trailer when they first started their business. One of our drivers hit a culvert getting off the road and ruined the front axle. The trailer was loaded with freight but the driver got it up into a parking lot and had a mobile tech swap the axle out. It was also too long. Being the only axle in west Kansas plus a loaded trailer needing delivery.. the company told him OK.
Well it wasn't OK.
The trailer wouldn't track the truck. The =company said they wern't going to put more bucks into the trailer. I had the misfortune of taking a load with it on a 480 mile run. The trailer acted like it had half flat tires. How will the OP rig handle ?? Try it and see but watch the trailers tire wear.