[sdiy] how to double Si diode voltage rating

[anthony]

If I wanted to use some Si diodes in a bridge to increase their voltage, 
like say I wanted to use 200V BY251's in a bridge with a 300VAC secondary, 
would putting 2 in series suffice to double the voltage they can handle? 
That is, would I use 8 diodes, 2 in series in each part of the bridge? Or 
would using these diodes in a bridge, singley give a bridge that can handle 
300VAC? When in doubt, is it better just to use more?

If I wanted to increase current carrying capability would I put the diodes 
in parallel? Like if I wanted to use 1N4007's (since I have a ton) and I 
needed 2Amps?


Anthony