I'm looking into my lst pair of quality oars. I've borrowed 7.5'ers for my 48" beam which is what Shaw&Tenney and others show on their charts/formulas.
They worked very well but... I've always been under the impression that the "goal" is to have all blade and no or as minimal shaft immersed.

Is that something to aim for? Slightly longer oars-7'10"-8'ers might give me more blade/less shaft in the water but until I can find a pair to try, not sure if that'll screw up the other rowing geometry/aspects or not.

I've decided on spooned oars if that makes a difference. I've read the old pro and con threads but like the spoons after trying them in calm and a little chop.
So...is all blade/no shaft immersed a goal to be aiming for or is 3-4" of shaft immersion normal on any length oar?
Thanks for any advice.