car trailer advice

Once I find a trailer it will have 10 ply tires. ( I sell tires for a living so I know that importance) As far as the tie downs it will also have 4 D" rings if I have to add them myself. I prefer a 16' or 18'. I have no need for anything larger. I know some will say if its bigger I can do more with it but that would also mean others would want to borrow it more often! As I said in my original post I plan on a winch so thats not a question. One will be added if not on when its bought. The Dove tail information is good to know, and thanks to all who advised for electric brakes and dual axles. I have found quite a few of them on craigslist just nothing close. I'll keep looking as as I said I am in no hurry.
Any additional information will be appreciated.
Thanks
Rod