There are some eBay sellers who make nice visors too. Since they're one-size-fits-all, and since no two helmets actually fit the same size visor, be prepared to do some trimming and curve adjustments. They're also a little pricey for what you get, but I've found that some sellers will offer you a discount on multiple visors. You'll probably need more than one, since they're usually prone to breakage.
I've bought two visors from Rembrandt Enterprises on ebay now and have been more than satisfied with both. They were both for a Jango helmet (smoked tint), with the second one going into a JD Jango once it gets here in a few days. I've now got to buy a third one for my son's SE ROTJ. I've been so happy with the visors personnaly that I wouldn't think of buying from any other seller. Keep in mind this is only because I've found a reliable source that I'm happy with, and not because the other sellers' products aren't good. I wouldn't know since I've only bought from one seller. Anyway, Rembrandt's visors are a great product and always arrive within a week. Snapped a pic to share the quality.
I bought one for my JD but it was too small. Although the curveture seemed perfect it did not extend back far enough at the eye section. There was around 1/2" gap either side.
Maybe I just had a bad one ??
Tk-938, received my JD helmet today and dry fit the Rembrandt visor on the inside with about 3/4" clearance on both sides of the helmet's visor cut out area. Should fit perfectly as the curvature was right on as well. Hope this helps. I'll post pics as soon as I get them but it may be a while since I'm in the middle of a custom jumpsuit and going to take my sweet time on the helmet. Actually let me get a pic of the dry fit and I'll post asap.
Update-pic of the dry fit Rembrandt visor. Notice it goes past the mandible areas and just into the earpiece areas on both sides. Fits in there like it was made for it. Just barely long enough too.