I have hulled many trailers with a lot of different configurations. I don't like addon sway devices, I have seen trailers flip with them. I do recommend a WDH with sway control built into it. Here's a helpful link to some good info about hitch and sway. I hope you find it useful. How...
Because I sold tires and have had some great conversations with engineers, about the MFG recommended versus the sidewall spec. I run the sidewall recommended tire pressure, my Dullers are set to 40psi summer and 38psi for winter