Hello BR, mine measured 1.719 without the receiver. I would say 1 3/4 will be OK especially if it opens a smidgen wider. I used the "auto" wrench shown in the Howto thread. It opens to 6 inches or something crazy like that.
The last fellow that used it cracked something on the receiver and had to do a welding/brazing job to repair. If you remove the magazine door you will have no issues. He had the drive pin against the magazine door when tightening, I think. His was very tight and mine only moderately so.
I have the bolt gauge ready to assemble, I have been fretting on how to package it so it is not damaged in shipping. Could send it at the same time and get that show on the road also.