Steve, what do you think of putting the check valve at the connection from tank valve to fill hose, vice where you put it at the inlet to the gold filter? I think both have plusses and minuses, but keeping the maximum amount of connections protected from a rupture (and tank pressure venting through the rupture) is the major benefit of putting the check valve closer to the tank. My tanks have a male foster QD, but then if it was a check valve it wouldn't be able to be used for other than filling the tank (one way ointo the tank but not out of the tank).
So, I made a small double fitting, male foster QD check to female foster QD that I insert between the female on the hose and the male on the tank. This is only used for tank filling. I do like the way you did it, but it also brings into play the connection to the gold filter, the gold filter, the connection from the gold filter, and the connections/hose to the tank. Any of those mentioned in the last sentence fail and you have the tank venting back through the failure or rupture. With the connections as I did, your only potential failure that affects the hose whipping about wildly is a failure of the tank QD or male to female fitting I made. Just a thought?