I always got a shade bigger than I needed. Have an 18k Reese Elite now from last fifth wheel. Fits in factory pucks, so still no rails in the way when it's out. Sometimes I wish I'd have got the higher rated one, just in case, but so far every fifth wheel we're considering for full timing falls well below that in GVWR. Last rig was 15.5k.
John and Rebecca Dickson
Emma-8 / Little John-5 / Iva-1+
2013 Ford F-350 Lariat FX4, CC LB PSD, DRW
2015 Jayco Jay Flight 28BHBE (#8)