The half-life of GH is about 2 hours. If you are using insulin solely to compliment exogenous GH, then humalog is a good chioce. If you are interested in using insulin for it's own anabolic properties, then actually a slow insulin is better. I have use long acting insulin for the AM dose, and then humalog with the GH injection after lifting in the late afternoon....excellent results.
My Canadian friends seem to have no problem getting humalog, so I assume it is otc, or at least treated that way by most pharm's.