Hello !
Blizzard PPC & BlizzarVision had been design to fit into an 1200 Desktop case.
I've been using such set for a little while. I had no extra cooling.
The original Commodore PSU should be enough for this purpose. However, the Escom one won't be. There will likely be a power issue if you use HD, CDROM drive...
I was using a modified AT PSU. However, it's prolly possible to keep the original one, and to use external powered SCSI case for HD/CDROM unit.
I even had a Delfina 1200 into the case! However, I had a small cable to move the clock port slot ;-).
Then, I overclocked stuff (BPPC, BV ...) and added extra cooling. It was not a good idea really. I didn't feel real 'boost'.
The best way to get faster system is prolly to get the fastest memory and a MorphOS system to take advantage of the PowerPC.
I had a +15/20% speed up using MorphOS 0.4 + Amiga OS 3.x at Heretic II & co compared to plain AmigaOS 3.x.
Bye
Good luck !
Nico