Well, it's fitted. Kept the original Win M70 2-pc. unit (floorplate + triggerguard). Cut the Delrin spacer where I noted (so the magazine would fit), and filed (slowly...) on spots where the floorplate was hitting the bottom of the stock on each side of the magwell. Luckily, the filing is hidden by the floorplate.
One other thing: The floorplate's front action screw hinge was about .020" below being flush with the stock. This seemed to be a major reason why the floorplate was binding at the release. A trimmed rubber washer seemed to square up everything by raising the hinge up flush with the stock, so now I can activate the release without difficulty.
