I used a 5/16” bit to get the depth and then a 3/8” hammer drill bit to round it out enough for the bolt and wedge to be pounded down.
It worked perfectly.
I have not decided what I want for a roof as of yet. Sorry I can’t answer definitely but I can’t see why a roof cannot be erected. I loved the design of the brackets. Made building the structure pretty easy. Would recommend TopCon concrete anchor bolts rather than the expansion bolts that come with the base plates.
I would not do that....the brackets are strong but a 20' beam is allot. I used middle brackets for a 16x16 carport, 8' 4x4 length, 16' sandwich 2x4s on front, middle and rear and it seems to be holding up .