I didn't think it through enough to mic the MDF, seems kind of obivious now that you mention it. It is the leading end that's a touch thinner though.
A second question I thought of after the fact, once I get the lams where I want them and I sand an angle on the butt ends, is there any reson that I shouldn't glue those ends together prior to putting them on the form? Basicall making one long lam.
I have heard horror stories about trying to keep them together when getting them clamped up.