If your remains are medium brown, then you're getting the proper heat.

The contents of the bag turn slightly gray like a spiderweb lost in a sudden gust but there is absolutely no visible vapor.
That makes no sense. If you're getting "contents" in your bag, it's vapor. If you think that vapor is as visible as smoke, you're wrong. A lot of the time you need to exhale in the proper lighting to see exhaled vapor.

As for not getting as high with vapor, vs. smoke, I responded to that aspect in your other thread about efficiency.