My understanding was he suffered from severe targit panic while shooting instinctive and went to the sights to cure this problem. Doing so, he found out how effective it was and continued to use it thereafter. The vast majority of his animals were harvested while using sights.
He used a four pin Merrill Heart Shot sight with pins set at 15, 30, 45, & 60 yards. For in between distances he would bracket two of the sights. He was very deadly with this combination and turned out to be one of the better shooters on NFAA outdoor courses for many years.
How have you been, Rod?