Boss SD1 (or similar) - Pros/Cons to swapping clippers in D4 vs D5 vs D6?

[drumnbum]

I'm modding my SD1 and I was wondering what, if any, pros/cons there are to swapping out the stock clippers for LEDs/Ge/Si in the first clipping position (D4) vs one of the other two (D5 or D6).

For example, right now I've swapped a 1n4001 into D4 and D6 and I have a Ge in D5. 

I've been experimenting some, but I'm just wondering what theoretical and useful reasons there may be to doing it in one position vs the other(s). 

In other words - if you were to swap out only one part, what difference would it make if you put it in D4?  What about only D5? D6?  Just trying to wrap my head around the overall differences in each position. 

[Mark Hammer]

Don't expect to hear much difference.  Generally speaking, the upper/positive half of your input signal will be pretty much the same as the lower/negative half.  So whether you clip the upper with one diode and the lower with 2, or the upper with 2 and the lower with one, will be largely inaudible.

Changing the overall clipping threshold, by using diode types, or numbers of diodes, with different forward voltages WILL be audible, though.  If you replace the single feedback diode with two diodes, such that you have a 2+2 complement, rather than 2+1, you'll have something more in the viciity of a Timmy.  A little more dynamics, a little less clipping, and a bit more output level.

What sort of sound are you aiming for?