Adjustable fork stop

I have swapped out the 35mm forks for 40mm on my 78 390. Others have posted about the triples contacting the tank. I was prepared for this as I read someone else had already addressed this issue. I read some different solutions but I needed to use my standard formula (cheap+easy=good). After some hardware store scouring here is what I came up with:
These parts are available at your local hardware store for under $10. The rubber part is an expandable plug. I plan to put some silicone in a large vacuum cap and place it over the end of the allen screw.