@Ryan H. Joseph
Ryan very good questions. A few tips below:
1. Remember, that the best results for Direct Mail is consistency. Plan on making a commitment to mail at least once a month for a minimum of six months. If that is not in your budget, do not waste your time doing direct mail. Find another marketing strategy.
2. You asked "Should I mention this will be my first investment property?". Why would you do that Ryan? Would you want to invest with a person who has never done a real estate investment deal? Do not lie, be honest if they ask, but do not feel obligated to volunteer your experience level.
3. You asked; "Can I follow the same techniques used for sending yellow letters to SFH property owners or do you suggest doing anything differently?" Any good List vendor can you give good advise on this question, but it is basically the same technique.
Its the List that makes the difference. For example the List for Apartments would be to target "Landlords with Code Violations list."
4. You asked "How much research on a given property would you do in advance? Would it be a waste of time to do any research or run any numbers before getting a call or feedback from the owner?" Having the correct List will minimize the research needed, but its always a good idea to do more research, just do not let it turn into procrastination from moving forward. The key is finding a motivated seller who not only wants to sell, but NEEDS and HAS TO Sell.
I hope these tips help you Anthony and I wish you the very best.