A little metal rod with a hole for the cross pin would close off the gas block, and would not require the sacrifice of a gas tube.
My plan was to turn a collar that slides over the gas block area with a set screw that would tighten down over the gas port.
I dont have a lot of clearance between my handguard and adjustable block so that’s why I was thinking collar. You would just have to have a selection of diameters and I think people would go for it.