I've fallen hopelessly behind my own build post, but just to experiment, I ordered one of harness wires with a spring connector end. They seem to fit very positive. Note they distinguish diameter of glow plug stem (OS-F slightly larger than regular plug).
And I tried one of these 1.5V, I'll call them 'regulator' module. I tried different configurations of LIPO/NIx source batteries & always got the same results, 1.5V & ~ 2.5A on new dry plugs. So I have 4 more on the way. The plan is to snip off the plunger plug thingy & hook up 5 in parallel through a rudimentary box with dedicated on/off switches.
There are also dedicated 'on board' RC ignition modules versions like the one offered through Just Engines, but that would involve a dedicated throttle servo & servo driver. Ends up being about same cost on my side of pond.