I have a 5x10 trailer and want to lengthen it to 12'. I bought this trailer because I don't want a 6' wide trailer (which all the 12 footers were when I was looking.). It has a single axle rated at 3500 lbs., so should be able to handle 2 hydro walks on it I'm sure. Right now I can just fit one on there. Has anyone extended trailer length? I assume it's easy to have it done at a welding shop? Would it be ok to have the axle right in the middle of the trailer bed? Or would tongue weight be too little that way?