Zener clipper cct (help request)

[Cliff Matthews]

Just a low budget project with most parts I've collected for a while. I'm wiring a flexible bank of transformers supplied with 2 types of variable mains regulation:
1) transformer buck/boost 2) zener clipper using 4x 50watt studs each with 6amp rectifier (so zeners only work half cycles)

Questions: Provided I have good heat sinking, is the clipper cct's fuse size correct? and can this cct be optimized?
The caps everywhere I assume will smooth noise, will they make much difference?

edit: Sorry, fuses, switches, diodes are missing in TINA (diodes are *6A08's, etc.. Go easy, this old guy is still learning 
and I've had those expensive NOS zeners for 20+ years and a bunch of .022uf 600v film caps just itching to get used..