downgrade #gs from 5.0.1 to ios 4 - few questions

[moshikoy]

hello
After upgrading to 5.0.1, while preserving my baseband for ultrasnow unlock
i am sick and tired from this slowness, battery life is shorter and with reception problams i have since upgrading so i decided to downgrade to ios 4
so i currently have an OLD bootrom 3GS iphone, BB is 05.13.04
i have shsh saved for these firmwares (See attached file)

my questions are:
1. is to which firmware is best for me to downgrade to?
2. should i be worried about losing my BB unlock due to this downgrade?
3. do i need an older version of itunes for this?

any guide or tutorial would be great

thanks,
Mosh

[tacoma96]

Easy way is to restore to 4.1. Apple still signing iOS 4.1 for iPhone 3GS. Make sure you preserved baseband with sn0wbreeze or redsn0w and if you installed Tiny Umbrella before make sure "set host to cydia" under advanced is un-check. Open iTunes and select the custom firmware to restore.

[moshikoy]

getting error 20
tried the thing with the hosts file - didn't work?
maybe wrong itunes version?

isn't going to 4.3 is better?

[tacoma96]

Put your iPhone into DFU or Pwned DFU mode from redsn0w to avoid getting iTunes error.

[xboxbml]

4.2.1 is best on 3GS...I always say...

[gmaslin]

Guys, what is the safest way to unlock and jailbreak a 3G. I just received one and have no history so I would like the most cautious route.