Trailer Changes

Considering removing the rollers and replacing them with bunkers. Bunkers would be about 4" x 10" and beveled to match the hull angle. Why, have always had bunkers and believe rollers don't give as good support as bunkers. Any comments or suggestions?
Also, the trailer only has a single axel. Believe another axel is needed. Hammer was good enough to post pictures of the inprogress boat transom repair. In one of the pictures youi can see the rear of the trailer. Have no ides of the trailers capacity as I bought (stole) the entire rig in mid December 2006. As a matter of fact, have never riden in the boat. Any comments or suggestions?