my only suggestion would be to use 3/4" mdf instead , but if its already set up and covered in vinyl
or plexi , i would say to try and use the threaded inserts.
using bolts on the plexi can lead to cracks when installing them , or , you can also crack the plexi
when drilling the holes for them.
i know the odds are against the plexi cracking , but if it was me i'd check the threaded inserts out first.
if it works, you wont have ugly bolts popping through your cp.