It has a lot more to do with what material type, wall thickness, dia, etc... than the die you use.
As a design engineer, I can tell you there has to be a chart out there on the web that could help you. The ones I use are all proprietary, so I can't help ya there... But first you should know the answers to the following:
1) What type of steel are you using? Hot rolled? Some type of DOM? 4130?
2) What diameter? You specified 2"dia...
3) What wall thickness?
With those answered you'll be able to find a chart that list the smallest bend radius allowed for the specific material, wall thickness, and dia.
Most tubing benders have specific dies that meet practically all those criteria, but give a "generic" BR to all the tubes. For an optimally designed tube structure, the BR of each joint would be adjusted (larger or smaller) to meet maximum strength, weight savings, or some other desired parameter...
How are you planning on forming these bends? Odds are you will design to the "low-cost manufacture" design parameter, meaning all your bends will be one radius, so you only need to buy or use one die. Get the die that fits your tubing size, and makes a bend with a radius as big or larger than the chart-specified minimum.
[QUOTE=SnowdogMarc] YJ's don't get stuck....they get temporarily impeeded in their forward progress.[/QUOTE]
I'm patiently waiting for the "foot-in-mouth" moment to end... but since I've posted, its not today