I went ahead and drilled out a hole with stepped drill bit--with a little olive oil rubbed all over it, thanks for the tip. It's at 7/8 now and I'll probably make it 1 1/8" later on. But for now I'll just start with 7/8 holes. I need to add one more slider vent towards the front, and then a capped nipple in the rear.
"Antonio" Bandera, Mini WSM, 18.5" WSM, Hasty-Bake Suburban, GMG Davy Crockett, OTG 22.5"