When I first started building LRs, I amassed 2 racks full and one day realized that those that weren't my personal hunting MLers were never shot and that I just wasn't a collector. So, TOW sold 3 and I did have an idea of their selling prices minus TOW's 33% which was high but seeing their website receives 1000s of hits a week, it was good advertising for my guns and me.....and it worked because all my subsequent LRs were sold by me based on the prices TOW sold them for.
Seeing my gunbuilding is a hobby, I don't keep track of the hours for a particular LR but do use methods which are the least time consuming. Was a toolmaker and all the new jobs had completion hours which had to be met or one didn't get new jobs in the future or no longer was employed by that company.
Also the great majority of my builds were spec LRs and I mostly refused taking commissions from individuals. Had one individual call TOW and inquired as to what builders were "fussy" and my name was one of those mentioned....this guy "hounded" me for close to a year before finally giving up......Fred