Your pump is a bit small to do it by brute force, i.e. pumping fast enough to maintain enough vaccum despite leaks but maybe it is possible. You would need to seal the MDF used as the jig so that there was no leakage through it. When the jig piece is on the table seal around the edges with tape so no air can infiltrate between it and the table. Make sure the fit between the jig and the part is very good so the part cannot move sideways. Get everything setup and see what vacuum your pump can maintain; if it is 20 inches or better that will probably be enough.
An open mind is a virtue...so long as all the common sense has not leaked out.