update:
I used the acrylic gesso for the oil paintings I'm working on in this WIP thread:
http://forum.portraitartist.com/showthread.php?t=6717
They're much smaller than the above portrait, and I think the gritty texture bothers me a bit when I'm trying to get detail. So I've been doing some more research and I found some information on the Golden website:
They suggest a clear primer for oils made up either of 4 coats of acrylic matte medium, or of 2 coats of GAC 100 and 2 coats of the matte medium. They say that this has sufficient tooth for oil painting and will prevent oil penetration.
I may try this next.