I've sealed this one with black modelling compound I have owned for maybe 25 years... in my studio (used to support products on small black bases). I have bought one helical Leica adaptor (for closer focusing) from Cam2UK on eBay - would not infinity focus, returned for credit in December, still not refunded - do not deal with this seller under any circumstances they are not really in the UK and don't respond properly to communication.
For Leica M I found an affordable s/h Novoflex adaptor and I would only advise Kipon, Metabones, Novoflex, Voigtlander or similar adaptors .
Been out on Sunday trying to find some decent light and a modern architectural subject - seems the south of England/Midlands has had wonderful weather but we've had very poor cloudy light in Scotland and it was a wasted afternoon. I also realise just how little decent new building has happened in the last five years here. I had not really understood what an impoverished period this has been. All the interesting civic or public architecture dates back 10, 15, 20, 25 years. I was prevented from photographing Cameron Toll shopping mall in Edinburgh by a security guard, nice enough guy, chatted for a bit but his brief is stop all photography even of the exterior of the building from the car park.