Direct mail - how many to start out with

[John Hixon]

Getting ready to start my first direct mail campaign.  My question is: How many yellow letters should I start out with?  500,700,1000?  I will have another person make the yellow letters.  All I will need to do is put them in the envelopes, stamp and mail them.    

Obviously the more the better, as far as a potential deal is concerned but I do not want to get overwhelmed with calls.  I work a full time job and would be returning phone calls during breaks or after work.  

What are your thoughts?

Thanks.