Lance 1121 compatibility

I know you want the largest that will work,I think the more important factor is the Center of gravity, which is the balance point of the TC-where the weight of the TC is the same on the front of the TC as the rear. In a TC made for an 8' truck bed the COG of the TC is going to be farther to the rear of the truck putting more weight on the rear of the truck and taking weight off of the front(steering) of the truck. Then you get into handling problems.Believe me this is not enjoyable(nor even remotely safe)to drive. Each TC manufacturer lists the COG of each model in a brochure. You want it to be over the rear axle or possibly a little forward rather than behind(although with a dually you could get away with some behind, depending on the weight of it). Slideouts are great, but add a lot of weight. You might want to look into a popup TC.