optimizing for speed vs. quality

[Graham Percival]

Does anybody know how to turn on (or turn off) various settings?  I'm 
trying to populate:
http://lilypond.org/doc/v2.11/Documentation/user/lilypond/Avoiding-tweaks-with-slower-processing


Although those docs are aimed at optimizing for quality, I'm also 
interested in listing optimizations for speed.  Joe, is it possible to 
(easily) turn off the vertical skylining, or any other improvements 
you've made?

(not that I don't adore the changes you've made; I'm just trying to 
separate the `notes/rhythms' phase from the `make it beautiful' phase.  :)

Cheers,
- Graham