Marketing - mailings

[Dave Rav]

Group,

Thanks for checking out my post.  I'm a fairly seasoned investor, but trying to step-up my marketing campaign.  I've been focused on mailings.  Marketing is directed toward absentee owners of SFRs - houses and MHs.   Some questions for those more experienced than me:

1)  postcards vs letters - which has better response rate?

2)  How long to wait between campaigns directed toward the same list?

3)  How many "touches" on average to garner a response?

4)  How do your leads prefer to contact you?  (phone call, text, email..)

I'm open to any and all input and feedback.  Thanks!