1. There are two well known flashers, E3 flasher & Progskeet flasher.
Originally Posted by Kailey283
The E3 flasher is not compatible with nand PS3s, only with NOR PS3s (which is most of them).
The Progskeet flasher is compatible with both nand & nor.
The E3 flasher is a solderless flasher.
The Progskeet usually requires soldering unless you purchase the solderless attachments seperately.
From what I've read, there seems to be more info surrounding the E3 flasher & the process seems easier.
Out of all your PS3s, the only one which is downgradeable to 3.55 & below is ceche01, which as ConsoleX has pointed out, has a nand chip.
So the only reputable flasher that will work with your PS3 is the Progskeet flasher.
2. You can find the list of resellers on the official sites of the flashers.
Word of advice: You might want to stear clear from v1.2, a lot of negative reviews for that one.
3. Is it worth it? Well the matter is subjective.
Weigh up the cost & benefits & make a decision.
If you don't want to go through the hassle yourself, pay some one else to do it for you.
CFW is awesome, that is for sure.
4. I've no idea how to totally strip the FW.
I've been able to view & extract the FW PUP but can't open the pkg files using the normal tools such as pkgview.
I've only been able to open the files using a hex editor (HxD).
Do some reading on PS3DevWiki, you'll probably find the answer there.
Few good stuff to read.
It might also be advisable to use help section, you'll probably get more help.