Only suggestion I'd have is to not weld it to your trailer. Spend a few extra dollars to have your fabricator make a bolt on plate, either with u-bolts or two plates and bolts. You may change your rig over time and the balance will likely change, being able to adjust the winch mounts location can be very handy. Just a thought...
"If you dont do it this year, you will be one year older when you do"