Capt.Your rubber stoppers are moveable so they don't figure in to the equation
The diff between 10 ft and 10 1/2 ft is negligible. Ten ft being a standard length you will find many more of them available.
I use 10 ft oars on my 15 ft cat, 15 1/2 ft raft and 16 ft raft. Ten ft is a good length for all of them.
Remember you can always move your oar towers in or out a little to get a different feel.
Enough talk about oar lengths for now. Get Out There and Row your Boat!!! This is the first time we've had good flows since 2011. Go Git Sum!
Peace,
The Capt
thanks. I've got well more than 2/3 beyond my oarlocks.Actually, the 2/3 below the lock is a pretty good start. I did mine via the dink around until it feels right method a couple of years ago and just measured to discover I'm about an inch off of 2/3 on a 9.5' oar. I row a 14' SB.