Here is the repro MPF opto and target button Channel as well as a spreader / light baffle. I am still yet to design a modded version with the baffles included in the channel bracket design so people don't have to get both items.
The parts can be found here:
The MPF channel is a replica of the original which is laser sintered 3d printed so is solid nylon, and will be stable and highly unlikely to warp.
The Add-on is the spreader / light baffle. Simply line up to determine which 2 screws to temporarily remove from the opto boards and then insert the Spreader / Baffle and then re-install 2 of the screws again. This item will rectifier any warping by straightening your. The advantage with this design is you can still see into the channel to check things are working while removing the warp.
here is the 2 items and target buttons assembled to give you a better idea.