I put about 2' of 11/2" pvc reduced to 1" with a check valve and a spray bar . I was surprised I thought I would have to reduce flow conciderbly but that little bit of 1" pvc really reduces your flow so if you can go all 11/2" that's the way id go.
Hd didnt have any threaded to barbed adapters. So i got female threaded x slip and reduced down to 1 inch with a bushing