Here's a specific question:

I know the legato (used for slurring up to the note) fingerings for E4, F4, and F#4, but is there one for Ab4 also? The piece I need it for is Bourdeau's 'Premier Solo' bar 17 (slurring up to the Ab4 from E4) if anyone has any other tricks.

try the D and C hole with Eb key on left hand plus just the G key on the right hand.

Try:

LH 1-half hole/2/3 ( resonance Eb, L4 )
RH thumb Bb/5-f key

Whisper key also helps slurring smoothly

Jesse Read
jesseread.com
http://www.twango.com/channel/StrollintheCool.jesse_CDs

My favorite fingering works for:

Slurring TO or FROM E natural and E flat

It's 100% guaranteed no crack (forget that lift R.H. index finger for E, that only works on slurring up and only half the time anyway)

It works different on different bassoons, but on the E you either hold down or flick the C# key (LH thumb). On lots of bassoons, holding it down makes the note out of tune and you have to adjust it with your embouchure. So if you decide to use it with flicking to slur TO Ab, you'd press the C# key down RIGHT BEFORE the slur up to the Ab (so at the end of the E). Take a few times to try it out and see what works.

And you got it.

No more cracks on any E or Eb slurs up or down ever again.