Brian --- No harm in sending out multiple letters of inquiry to foundations when you know and observe their guidelines and areas of interest as you are wisely doing. Foundation officers will tell you that you are steps ahead of most organizations which do not understand the importance of research in determining which foundations are the most likely to be receptive to any communication, and that a “scattershot” approach will be ignored by them.
As you are sending your letters in the way in which you describe, here are a few things I have learned over the years when my organization did the same.
(1) Watch for P.O. Box number addresses. With no idea where those letters will finally land, look closely at the complete listing of the foundations’ officers and any staff. Take care should any individual be identified with more than one letter. Foundation officers I know routinely put such duplicate letters in the waste basket. (Not only observe where the multiple letters are heading via a P.O. Box, but watch for the same bank, law office, CPA firm, etc., to avoid the same problem.)
(2) If possible, try to work in a line or two, or some reference personal to the foundation --- something you gleaned from where it gave its money, some historical recognition, etc., all to make the letter a bit more personal and which suggests that some thought went into it. (Our letter to the private S. K. Wellman Family Foundation recognized that Mr. Wellman as the founder of the company of the same name which was one of Cleveland’s oldest, and most respected, corporations.)
(3) If your organization is so situated and has the means, be sure to suggest a site visit to your facility --- with the caveat that there will be no solicitation made at that time. Even if they decline, chances are they will say “thanks anyway,” and chances are even better they will remember you for the invitation. They might even say, “maybe some other time.”
(4) And, of course, I know that before you make any mailing, you will ask your board members and other of your leading advocates to review the names of foundation officials for any of their possible friendships and contacts to determine if they might sign some letters, or if they would separately follow-up with their notes of endorsement. Some might be in a position to make requests that some of the foundations consider giving you a hearing.