30,000 megaohms is not at all conductive. I'm not exactly sure about that datasheet because you need an amount of something to measure resistance (you have to say, 1 inch * 1/4" piece has x amount of ohms). I think all they are trying to say is that it is virtually non-conductive.

I'm here also, a little late, but the same BBJ as the Spudtech forums.

Aluminum melts at around 1200 degrees, and lead at 600 (F) so you probably won't melt through, but its still not a good idea. Melting something like zinc would probably be cheaper than solder. I've done it - just get a bunch of pennies from after 1982 (might be 1981), and they melt very easily, and ...

A larger spark has a greater chance of ignting fuel that is not mixed properly, because it covers a large area, but if you using a chamber fan, it should matter.

You might also try keeping the torch head on, and slipping a hose over it, then you'll have a correct mixture and you won't have to worry about timing.

You can also use Co2 beverage type regulators with paintball tanks. They are 1/4" NPT input, so all you need is an ASA adapter, and maybe a 1/4"x1/8" reducer (RATED FOR AT LEAST 1000 PSI). Check eBay for the regulators and ASA fittings. I've gotten a whole setup for around $20.