5052 might be the best combo of formability and corrosion
resistance, but that's just from a quick google
, you should do your own research
, and talk to whoever is quoting.
IMO many shops are going to avoid replying to an inquiry like this because of the strange shape (would a simpler shape not work
? Something with one big radius or a few well defined bends?) lack of tolerances, possibly unusual material specification (I think it's unusual to bend T6, should be annealed (?)), and low quantity. It just doesn't pass the eye test as customer knows what they want/something that's going to be easy to make money
on. These thoughts are related to your other posts about nobody wanting to do work, etc. The form of the RFQ matters, especially as a customer going in with no previous relationship, when 99% of competent shops are already booked weeks in advance with work they're comfortable with for customers they've worked with before.