Mick,
For the flatside tanks, I usually hang them from the ole' coat hanger hanging from the top of the booth, then I spray the complete tank, then add a couple coats of HOK clear.
Then I mask up the backside of the tank up to the rear mounting bracket (then of course sand the tank so it is ready for graphics). Then I can lay the tank down to reclear after the graphics. So now you are reclearing the side and the bottom of the tank (the inside is masked up)
I hang these over the corner of a small table I have so I can get both the small "angled" front of the tank, and also the portion rear of the bracket.
Works just fine. No dry spray and very little edge. It is on the welded edge anyway.
Hope I explained this well enough.
Another tip is to hang the "smaller" end of the tank up (instead of hanging down). It's too easy to run the clear. Especially on the pointed stretch tanks.