Here is a thought, if you are looking to rough them out for drying purposes why don't you use the dimensions Pat gave above for the recurve and if you decide to go long bow you only need to take of limb width later.
I've not used Elm, yet, but with the hickory recurves I want at least 1 3/4" width. The current hickory recurve with the sinew curing is 1 7/8" +/-. I think Pat has hit it on the head.