I sure agree with AvaBob that forward roll at the end of the pattern is in many instances a nice thing to have.
Axis rotation of from 20 to 40 degrees in many cases makes a lot of sense on today's patterns!
Then again how do we explain the senior tour year of Pete Weber with his stronger side roll? I thought I noticed a slight tweak in his roll at the tournament at the Villages in Florida where he won for the first time. Creating a little less side to side motion. The rest has been history in this record breaking season. I think we would all have to agree on that!
As to conventional grips and Dave Davis. I was fortunate enough to stumble in to a house in South Florida and end up getting to meet and then over a period of time subsequently bowl with Dave Davis. This was around 1998. At the time Dave had just finished winning a couple of USBC Masters titles for big money and over the next couple of years was throwing the ball fantastic!
He had a knee that was healed up with special treatment from a long period of painful accommodation and was throwing the ball fantastic. For a year or two more he was throwing fantastic and leading and winning more than one event on the PBA senior tour.
I have watched videos of him early in his career and none of them reflect what I got to see at this time in his mid 50 to late 50s with his dramatically improved knee!
https://www.youtube.com/watch?v=yk_cOVvpg-I At this time he was fast around 17 mph at the pocket elegant and with a beautiful full fingertip forward roll style! Enjoyable to watch like Parker Bohn.
As to a conventional grip I knew none of it, though it may have been a fact. I know he was famous for a four step delivery, (though he was five step by then), and his effortless speed. I know watching him helped my own bowling and learning of his practice regimen which he used most of his bowling career.
I remember him telling me of when he converted from being a full roller to a semi roller and if I remember right, it was months of changed roll practice with no steps!
I feel lucky and honored to to have stumbled upon my relationship with Dave and frankly wish I could still see this elegant style several times a week like the good old days. I felt I never bowled as well, just because of osmosis!
Regards,
Luckylefty
PS as is well known Dave is a fine Gentleman, outstanding sportsman, and fierce competitor.