I have been running this setup for 3 years on my Hobbit with a 21mm PHBG and my carb only fell off once when I was first tweaking it.
Find radiator hose that'll fit snug over your intake, then hoseclamp it to the intake. Then find a short (2-4") piece of steel tubing that will fit into your carb. Clamp the carb to the steel tube, then clamp the other end of the hose clamp onto the steel tube with a hose clamp and presto you have an angled intake that lets you mess with the carb and costs like $5.
Here's the only picture I have of my bike at the moment where you can see my carb (edited)