Hoya lockii will not be lost to me any time soon as I have a large number of plants now, and for the most part, they all look good.  They are quite happy growing in sphagnum moss mixed with a little bit of bark.  They all grow in well-lit, warm, grow-tents with day time high temperatures of around 77°F, and Night time lows of around 60°F.  I have enough plants now that I may try moving one into the regular house and see how it does for me.  I think it may surprise me as its close relative H. papaschonii is doing quite nicely upstairs in a dark northwest window.  The entire secret was discovering that it likes to be constantly damp in sphagnum.  Here are a couple of close-ups of the flowers from a few days ago: