So, I cut the wing lengthwise at the aileron cutout, cut off the leading edge at the ribs, removed all the shear webs and nailed the whole wing flat to the board. Replaced the LE with laminated 1/4" stock, added LE gussets on each rib, replaced the shear webs, added a second set to the front of the spars, and re-glued the trailing section. Sanded the top smooth, unpinned it from the board and - and it's still bowed. Less, but still there. Next up - surgical removal and replacement of the main spars by running the wing down lengthwise down the table saw. Here it is while still pinned down.