Hi, Larry...
I think the broad-blade propellors were intoduced on the H-6 version, but I think it was the standard style narrow blade and small spinner that was used when the aircraft first came off the production lines late in 1941.
The H-6 was developed initially for the torpedo-bombing role and after extensive testing at Grossenbrode in Germany and Grosseto in Italy, I.Gruppe/KG26 did their conversion to torpedo-bombing at Grosseto in early 1942.
The attached links from Ed West's
5-10 batch of photos show two 6.Staffel/KG26 H-6 machines with the early style propellors and spinners, as well as differing camouflage schemes. Unfortunately, I'm not sure exactly when these photos were taken, so it doesn't necessarily answer your question when the broad blades were introduced. I should point out that I couldn't connect to the site after posting these links, but I'm sure you can refer back to Ed's posting and try from there.
Regards
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