Zoltan,

Your thrifty Hungarian friend sez: Yes, try the cheapest first.

Actually, I'm in the process of using exactly the same 20oz.  BL Head Gasket
Repair myself, and I'll post the results in a couple of days.

To bleed all the coolant out,  take a garden hose, put a 3/4" iron coupling
on it, and stick it in the top coolant  hose that goes to the tank. Turn it
on lightly, run the engine, and the coolant all comes out the bottle.

When you've done that until it runs clear, take off the radiator hoses at
the joint on the firewall (on my 1.9) and do the same thing. When all the
coolant has come out the bottom one, hold your hand over it and it will all
come out the top one. Then stick the garden hose into the coolant hoses that
go into the engine and turn it on. After you've done this for about an hour
in freezing weather, confirm that your fingers still bend, and unwind with a
short glass of Tokai, 5 Putonyos. Egri Bikaver will not do.

You're right, this product is not designed for "our" engines. Before using
it I called the people at Bar's Leak and talked to a friendly guy there who
said that between 10 and 20% coolant left in the system will probably be ok.

Anyway, I'm trying it right now--it's there in me engine as I type--and I'll
let you know what happens.

Though the instructions say to leave the heater valve open, I shut both of
mine. I don't have heater core leaks and I don't see what good it could do
in there.

Keep your fingers crossed. If they aren't frozen.

Geza