Mailers Quantity vs. Quality

Is it better to mail out more cheap material, or to spend a little more and present a better mailer?

Good afternoon everyone. I just completed my second order or mailers and was wondering what works and what doesn't. I'm mailing in the Silicon Valley, a.k.a. the Bay Area in California where there are very little foreclosures and motivated sellers so our letters need to be tailored to people who just want to sell their homes without going through the drama of an open house.

When ordering, I noticed a lot of different options like having an actual human write your addresses vs just using a handwritten font. These options cost more, but make the letter seem genuine and probably increases the open rate.

What has worked best for you? What options are worth it and which aren't?