It sounds like I may be a little late in posting this, but I thought it might help for future reference... a most generous and talented Korean friend gave me a kit for a Yoshioka Flash which (I hope) is perhaps similar to an MK kit and gave me pointers on building it so maybe this info can be passed on. It is a symmetrical airfoil, tapered wing design with a straight trailing edge, although this technique should work for a swept TE as well.

Using two pieces of ~ 1" aluminum angle stock long enough to span a wing half and a flat building surface amounts to a simple wing jig. IIRC, center lines are drawn lengthwise on the inside of the LE and TE; pins may be located at multiple points between rib stations as a guide. The LE and TE are tack glued to the top of the waxed angle stock along the chord line (through the center of the airfoil). You can build right over-top of the plans or if everything is notched, just the flat surface alone.

Another technique that works very well for the fuselage is to assemble formers, firewall, and fuse sides dry; hold together with rubberbands or tape. Now place pins on the center top of all the formers and firewall, then hold L and R fuse sides in either hand and use line-of-sight to line up all the pins with one eye shut - start glueing...