Hitch Extension Questions for Pulling a 7 x 14 Cargo Trailer

i have a reese 2.5 inch diameter hitch extension that was 48inches at 4000 lbs and at 41 inches it was 5000 lbs i shortened it to the 41 inch length and pulled my 7x18 enclosed trailer behind my truck camper with no problems but you definetly need to pay attention to tongue weight balancing your load in the trailer is a must