We grew up camping in the 70s and 80s in my folks Jayco Jay King.
.never a leak. We bought new Coleman pup in 01 and never a leak. We took delivery of a new Roo last month and it leaked, but it was my fault as some canvas got caught in the seal. Since then no leaks and camped in the rain...no leaks.
Sorry about your struggles...good luck. We had a 30 footer feather lite and our 23 foot roo has way more room, better beds..my wife has back pain and on our maiden voyage, she had an excellent sleep all week...we joke about sleeping in it versus our own bed...
Bob, Tonya and the kids
11 Rockwood Roo 233S
08 Grady White Seafarer 228
08 Tundra 5.7 liter 4x4 crew cab TRD limited
08 Toyota limited 4 Runner Iforce V8 full time 4WD, tow package