Glow plug recommendations

[Gee]

Hi guys, I'm giving nitro a try for a while. I bought the neighbors Jato 2.5 and in the same week got the Duratrax Raze Truggy. So far I've been give four differnt glow plugs from the LHS's when I asked what kind to use. I live up in the Pacific Northwest (not the rainy side) if it matters. I'm also running 33% in both of them. So what glow plug would you recommend for....

Traxxas Jato .15 cu in (2.5cc)
and
Supertigre G-27CS .27 cu in (4.4cc)

Any good places to pick them up at, quanity discounts?



Also a little confused on the .15 and 2.5 numbering scheme. Can anyone shed some light on what the numbers mean?

Thanks.