I have been tuning my own harps and customising them for years now.
I can't really comment on the Farrel tools but I believe that they are
very good.
As for tuners i would buy what you can afford.
If you can afford it get a strobe tuner, if you can't get a Good
quality Chromatic tuner (Korg) have a pretty good reputation.
The Lee Oskar tool Kit is excellent I have had mine for years.
The Hohner tool kit is also good.
I use a couple of Dentistry tools that I found at a boot sale as well.