Tried going back to conventional putting, but was not matching what I was doing with the longer putter anchored. So I decided to experiment to determine length and weight of an upright legal putter that I could use in a similar manner without anchoring.
End result was a center shafted Maltby CNC CSS701 head 360 gram. I have always liked this head as it is carbon steel and for my purpose has a fairly rounded sole. My goal was to set the putter up with a 10 lie (to be legal) and then actually putt with my eyes directly over the ball - meaning the putter would have the heel of the putter up at 10. I used a straight long shaft I had on hand and trimmed so that my putter is 39.5" in length - 17" round grip. Fashioned my own adapter using a 3/8 bolt to create the exact angle desired.
I putt one hand at the top without anchoring and the other hand down the shaft and use a pendulum stroke. I am putting better with this than I did with an anchored putter. I putt with an open stance, head directly over the ball and a great view of the line.