I'm not sure posting your email address in a forum is a good idea, but it's up to you.
Technique is also key in replacing read/write heads. If the heads are at all twisted, bent, bumped, or even touch anything during the process they are usually ruined. It's why guys will spend thousands of dollars on specialized tools to make it easier sometimes. Also matching the heads is key, if you're following Donor Drives guide (http://www.donordrives.com/hard-drive-pcb-donor-match
) then you should be pretty good. Also keep in mind that if there's media damage (scratches) even damage too small to see, it'll instantly ruin a new set of heads. Seagate is especially prone to this problem.
I'd recommend that you first hone your technique by taking apart working drives, remove the heads, then reinstall them. If you can get that to work consistently, you're ready to try on an actual case. Also having a clean room environment is critically important. Dust can be quite fatal.