Why buy an expensive system. In my 3 engine SM 79 i made my own. I use a mini toggle switch, charge jack, C size battery holder, 2300mah battery and wire. I think I have $10 in each one I make. On a full charge I have gotten 42minutes of full time glow. I have 3 four stroke engine in the plane. I have not had one cut off yet. I have a switch for each engine. I actually have the each set up installed to the firewall.
I have not had failure of any glow plugs yet either. I just turn them off at the end of the flight. It works really well. I have done this for all my glow engines for the past several years.