I've been doing online and offline marketing for myself and clients for years and I always test and tweak to see how to improve results.To clarify my "I" and "We" comment.

Depending on the extent of the rehab, even the 75% rule can be tweaked a tad.

Any good real estate attorney may already have some on file that they can tweak if necessary.  

I’ll see what I can do to tweak it some from my end.

I like to run both and have both sets of numbers work (one for plan A and one for plan B), combine them both in an IRR analysis and tweak parameters to optimize the strategy.

RL's forms are state specific and can be modified after you receive the attorneys tweaks.

If you don't get at least 5% phone calls from your mailing, you need to revisit the source;I am more inclined to printed letters and envelopes with a good tag line to get people to open the envelope - I am not much for yellow letters;To increase your success rate, after you do the mailing, try to get as many phone numbers as possible for the people you mailed to - you can try to use whitepages.com, 411.com or intelius (fee based) - you might also want to visit personally a few of these properties, and talk to neighbors, to find out more about the owner.To me direct marketing is a 3 step process - good list first, tweak the mailing until you get 5% or better response rate, follow up as many as possible (via phone or personal visit.)Good luck!

It doesn't have to be major, but frequent tweaks will help.

When I try to ask about the condition of the exterior or interior, I'm met with frustration and impatience.I have made sure to tweak my marketing so it's not like most mailings you see: "I want to buy your house at 1234 Main Street."

You can also tweak your criteria and location until you have a list that fits your budget.