Sounds uncomplicated, right? You can do it with a drill, you can do it with an ice-fishing saw, so how come you can’t do it with a #%&$ curtain panel by pattern? I see lots of people fail by drawing a circle on the “Level 1” workplane of a panel family and make a void through a solid that is extruded from the built-in reference lines, then try and constrain it or otherwise wrestle the cylindrical void into submission. The problem here is that “level 1” is almost meaningless once you get the panel hosted into a divided surface. Level 1 essentially becomes a slippery, interpreted “best fit” plane that Vasari calculates between the adaptive points. I recommend that you forget Level 1 for almost everything and build off the points and lines that are baked into the panel family.