Hi there Kermit
Here is my opinion about paddle choice

Curved blade ( square end ) this gives me a smoother entry and more bite at the begining of the stroke , the square end help`s in shallow water ,more surface area than a round end , as for grip I would only use a wooden T piece the plastic ones are terrible . The modern makes are pretty tough I use Werner , and Waterstick (who are no longer in buisness due to the parent company giving up on the paddling side of production) The Mitchell paddle from the States gets a fantastic following by the openboaters .

As for length ,I had read books asked other paddlers , watched film footage , World champion Eli`s paddle seems to be about a foot over his head others the T piece was down at there chin , still not sure so I wrote to Bob Foote in the States , he recomended this sitting in the boat with the full blade in the water the T piece
is at eye level.
But remember it`s a personal thing like the way you like your tea try out diffirent lengths and find out for yourself.

Hope this helps

some folk are put off by curved blades as there are some strokes which are not so smooth with them, but I intend to try one because forward speed and power are often so important when in an OC1. With my thin arms I need all the help I can get.

I would only use modern quality synethic for WW. There are some good reinforced WW wooden blades but they are too heavy for me (thin arms again)

I use a tee grip, plastic, which required a lot of sanding to get smooth (no ridges etc), but with a micro rough surface (ie not glossy smooth). This provides good grip without giving blisters. But I have just made an oversized wooden tee grip to try with my curved blade.

I think tee handles are required for a stronger grip when in WW. I use a palm grip for flat water as it gives more options for flat water strokes, and more comfort for all day cruising.

My spare is a cheapo alloy shaft, plastic blade, but carbon/glass shaft with an oval grip is much better, and warmer. Warmth is pretty important as most WW paddling is done in winter.

Length wise I go short rather than long. I think you have to be more aggressive with a long paddle and I'm too laid back for that. Guess I'm a trad open boater at heart.