What radius die should I get?

I am building a pro tools hmp200 bender and I was going to order a 1.5" die so I could make some bumpers and such to get better at bending. I plan on pretty much just building my skill with the 1.5" die and/or using it for bumpes and random supprts in a cage or something. I will eventually get a 1.75" die for my cage. I am just wondering what radius die I should get for the 1.5"? I have been told to get the smallest die available but they go all the way down to 4.5". So the choices are 4.5", 5", 6", and 7".

Thanks Guys
Chadwick

Nothin?

the smallest available IMO

the tighter the bend, the easier it is to match existing geometry...

there are many times that I wish I had a tighter radius, and I cant think of a time that I wanted a biger radius...

well I guess 4.5" is what it is then. Thanks