Regarding the horn nock... maybe the groove was too close to the lower edge of the nock? Horn has grain like wood and can split if there isn't enough material there?
Just a guess as there is no pic.
As for the rest of it, I wouldn't worry too much about how it looks at brace. I've had Robert Hardy tell me one of my bows was upside down, just because I had a naturally deflexed limb as the lower.
Short of sticking strain gauges along each limb and wiring 'em all to a chart recorder, it's down to eye and feel.
Don't be too hard on yourself.
Yesterday at the club 'Taxi Dave' came up to me with 'Dogleg' one of the Yew bows seen on the TV... it had just exploded on him! It was always a tad experimental, and had a belly patch so we weren't too surprized (he needed clean underwear tho'
). It was made in April last year.
I'll lend him the 100# Elm warbow to see how he gets on with that. Much better making bows for mates than customers who live miles away and don't appreciate the vaguaries of wood.
Del