What kind of foam for gurglers (going for northern pike)

Going on a northern pike trip to northern Manitoba early in June.
Although most of my flies will be streamers, I'd like to make up some
gurglers. Last year, I used a few that I picked up somewhere and they
did well. This year I'd like to make my own. I think I know how to
make them, but I'm having trouble on what kind of foam to use and where
to buy it. I'm planing on using size 1 to 2/0 hooks. They don't have
to be elaborate, just functional. Online, I've seen 2 mm and 1/8" foam
strips. I think this is what I should be using, but I'm not sure which
size foam. Also, if I make about a dozen flies, how much foam material
will I need? Thanks.

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