newbie questions. appreciate needed help

[Yiftach Ilyov]

i just started out with whole sale, lunched my first DM campaign today and i have a few questions;

1.If i can afford it, how much should i budget for DM? how many letter should i send out in order to do a few deals a month? 

2. does the cliche "quality over quantity" apply in dm marketing?

3. What do i dont know and should ask?

4. MOST IMPORTANT- how can i know what part of town people has high equity in their properties?

thank you.