Hi John,
The only correction I will make to this topic is that not all regulators that have a DISS connection bypass the LPM setting. There are many flavors out there. There are regulators that have two air ports and both may have DISS connections (see attached picture). There are also those that have one DISS connection but no LPM adjustment.
If you have a two port model, the port beneath the pressure gauge will be the 50 PSI port. If your DISS is at the end near the LPM dial it is controlled by the dial and it probably will not work well with the demand valve. I posted this on the Facebook group. Its everything you need for a "E" tank, including the regulator, mask, hose, and demand valve.
The seller told me he has several to sell and will relist when this one sells. I say this because I hate to see a couple of clusterheads get into a bidding war.
Please note in the instructions about shipping. I was the first to buy from him and asked he throw everything in a medium flat rate box. I was the only bidder and got mine for $112 with shipping. EBAY Demand Valve listing