If you single point it, you can make whatever you want. 1.90-14 would give you ~.030 wall thickness and that much in threads too. TPI can be whatever you want. I've seen several taps larger than 1" use 14 TPI, so that's fairly safe IMO.
Since I'm guessing this goes towards a raincover, you could make a doughnut and drill/tap that at 90* angles and anchor it in that way.