I "adjust" wood forend fit and tightness by removing the spacer and flat sanding the flat side until the forend slips on the barrel with just a little resistance, just tight enough to keep the barrel from being loose when open. You can also change the hole position, but that's pretty much permanent and all but impossible to change back. Spacers only cost $4 and are easily replaced and can be shimmed real easy to tighten a forend.
TIP: A 1" square of refrigerator magnet placed near the muzzle end of the forend in the barrel channel will eliminate or reduce vertical stringing, some use a business card, but they aren't very weatherproof!
Tim