I suspect that the connection rate here is lower in H +, so I would test only in H. However, almost always connected to the H +, would like to know any code or application to disable H+ to test H.
You can't. It's all network side. You can only drop it back manually to 3G in the network settings but you'd find the speed of that intolerable.
Edit - Actually, I found this searching through my thousands of S2 bookmarks. I'm not sure if this will do what you're asking as I've not been through it thoroughly/tried myself as I don't need to, but I think it's probably your best shot at achieving what you're after.