I would beware that taichi has as much tendency to teach viable internals as aikido does (however you might wish to interpret that). Lineage won't tell you much either - there are plenty of guys coming back from China with only the outer form, but without the inner content. You have felt Howard, yes? So you have a basis for comparison. Go out and feel the guy and see what happens! If he is moving right, you know what it will feel like; if he is not, then well...
I agree with what Lee said and would add that you could post a question over on the Rum Soaked Fist
Request a Teacher forum and you'll probably get some recommendations. My experience is most of the gym and community center teachers are doing the flowy/qigong/health by moving type of Tai Chi and lack the real meat and potatoes of IP/IS.