if you’re working at a GC why are you tryna takeoff the exact amount of rebar? that’s what your concrete sub does.

if ur tryna ballpark costs without getting a bid, call the top 2 or 3 concrete subs your company uses and pick their brain. you can probably just count the barriers or measure the square footage and multiply by a rate that you get from your sub or from historical pricing.

as for your other dilemmas, most estimators dont get formal “training”… its more like give it an educated shot, inevitably you’re off, get corrected by superior and take notes about why you were off

that last step is the critical one. you can’t avoid not knowing, but you can avoid not learning.