Don't be fooled by 3.9, it's not as fast as a good 3.1 install, hence Classic WB 3.1 Full.
Having a Blizzard 1260-50, 2060-50 I don't see a big preformance increase when running 3.9.
Except when I use the CS PPC 060-50/200 with a 10K SCSI HD, then it's really a bit tad faster than 3.1
But I just got the Blizzard 2060, so I have to test with the SCSI controller, but it is still 50 pins and not 68 pins UW.