First off I think you might have a hard time doing 3d with a 350c on nimhs due to the low thrust/weight ratio unless you run a voltage that will shorten the motor life considerably. Lipos are the way to go here. As for Depron, have you looked at
www.depronusa.com? If the price is too high or if shipping is unavailable in your area try to get blucor or fanfold from lowes of a local building supply store, check out
www.foamfly.com for a lowes sku # on the blucore. Walmart sells foamboard with paper on it (that you will have to remove) if you get really desparate. Lastly, check out the HD3D arf at
www.allerc.com , its 28 inches, uses a gws 350, and is depron