There are formulas around which purport to predict the springback in bent laminations. I've not found one which works. I'd build a form and try it. With six layers, there won't be much springback. My first try on the form would be something like 48" radius, shooting for 49" after springback.
For big-area laminations like this, vacuum-bagging is the way to go. Look up vacuum veneer press. www.joewoodworker.com is a good online source. Use a non-creeping glue -- either urea-formaldehyde or epoxy.
You can make the bending form kinda like traditional wings were built. You bandsaw "ribs" with the desired profile, and skin them with thin plywood, using glue and staples to hold it in place.
You might also see if you can find "bending plywood" in your town. This is plywood intended for bending, just like you're doing. It is considerably nicer to work with than MDF.