Well.. the situation down there in Miami is that DM's don't get paid. You get to dive free.. but you're assisting so, it's not really a free dive. But, you still get lots of experience. As a DM tho, you may be able to work in the shop, and you will get paid for that.
As an instructor, from what I hear, you get $50 per student. That's not bad I guess, but keep in mind that these classes take time, so you're spending anywhere from 3-4 days to 8-10 afternoons per class. That's alot of time. Say you got 8 students, and divide $400 (50 per head) by the time it takes to certify them, and it doesn't come out to an overly impressive hourly rate. Also consider the money it takes to get through IDC, professional liability, diver insurance, etc.etc.. that's a serious amount of money you're spending for an un-impressive hourly rate.
But, that maybe just the case for my local area. Miami has too many instructors and DMs anyway.
Also, consider that it is inevitable that diving is a seasonal sport. Even in Miami, the winter was almost completely dead. After November, it was dead 'till just last week. With 0 customer days coming in streaks, no classes, and dives being canceled because of winter winds.... winter was seriously tough. And that's the sunshine state we're talking about.
On the other hand, summer is crazy. Starting this week, we're seeing drastic change, starting with a 8 person OW class starting today. I've been told that by April, the shop will be going crazy with people buying weights, signing up for classes, yada yada yada. The difference between on/off is huge.
My advice would be.. get instructor as soon as you can afford it. DM won't really earn you much, or you are lucky if it does. Get instructor status, and do it as a weekend thing while keeping a day job to keep the money flowing. First see if you can instruct and pay off the money it took to get instructor certified. Then think again if you consider making it your main source of income. Most people I know in Miami are not fulltime instructors.
Remember, as long as you are using the PADI system, they will always make you pay them in one form or the other. Be it further education to become a more credible instructor (speciality instructor courses), buying their newest useless gadgets, etc. etc.
Oh yeah, it might clarify things if I gave you some info about me. I'm in IDC starting today, and am planning teach this summer. I'd be lucky if that'll pay for my IDC fee. I'm affiliated with a LDS, and will be working through them. I guess I'm lucky because I already have a place that needs me to instruct. But even still, the seasonal change is so drastic that I would never consider doing it full time. Actually, I can't because I'd get laid off everytime the season ends. So, that's pretty much what it comes down to. I'm sort of half step into what sounds like your plan.
