The first heat shield I made for a 11.75 inch rim bucket was perfect for my hot pepper plants bucket, but too big for my blue dream bucket, as it was very easy for the light to be touching it. I prototyped an intermediate size (between the heat shield and the LST grid), in search of a universal heat shield size that I can drop ship. It works for my blue dream bucket, and I’ll have to test it in the future on more standard buckets (Lowes, Home Depot), and measure how far down the bucket it rides.
In comparison, my LST grid size seems to work for any bucket. It’s a little bit more flexible than the heat shield too.