I built a couple and wasn’t far enough up the learning curve myself to give the gunsmith good direction.

Too heavy contour
Wrong twist (too slow - made the mistake of following his advice and he was old school and not on the long heavy bullet train at the time.
Told gunsmith what i wanted but it didn’t dawn on my to write it down for him (he did not write it down and invariably both were wrong the first time)
Gunsmith was local, which was good to deliver parts in person and go see him to stay top of mind, but he ended up going radio silent on me for almost a year

I’ve made both of them work and both shoot a lot better than i can though so it wasn’t terrible. But with hindsight i would definitely do the things above differently