Which ever one you like is just fine given that the lines in the trailer are 3/8 to 1/2 anyway.
Have you thought about running a flow test between the two sizes?
Time how long each will take to fill a 5 gallon bucket with and without the regulator.
2016 F350 6.7L LB CC Reese 28K 2014 Chaparral Lite 266sab
"Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety." 2014 19 days camping 2015 17 days camping201620 days camping