Next time I would put the intake in the bottom right from the beginning because I have the feeling that it I have less struggle with wind since I moved it there..
I would probably go with 3" and 10" with a Weber lid, I've got a Weber bottom on mine for a lid so my top grate is flush on top. Thinking about different intakes.
I'm starting from the same position as you, Googled UDS Smoker and made one with the parts I could in the UK. Ie no Weber grills.
Owning a brewery means getting everything else is easy. We get our cider apple juice concentrate in lined drums.
Seasoned my UDS last weekend, first Boston Butt with cherry this weekend!