I've researched a lot about DOF adapters like the Twoneil Plus and Jag35 for my HV20, but when I saw a well-priced Letus35 Mini on eBay yesterday, I nabbed it.

It comes with a Canon mount, but I will be using a Nikon AI 50mm 1.4 lens. The Letus Nikon mount is somewhat expensive ($76 on B&H). Is there a good third-party Nikon mount that would work with the Letus?

Also, it doesn't come with an achromat. Is there a pretty good one that would be compatible with the Mini? I was thinking about this one, but I'd like to go even cheaper than $130:
http://www.jetsetmodels.info/pics/hv20achr1.jpg

I'm late to the DOF adapter craze and pretty green, so any advice I can get on a good first time setup is much appreciated.