Guitar technique for smooth jazz style?

Folks: I've been asked to fill in for a band in the studio. They play smooth jazz, a ala Grover Washington. What scales and effects/tones for guitar best compliment this style?

I'd appreciate any input because I am real excited about the chance to play in this role.

Thanks Mike. I was thinking compressor, slight chorus and maybe my Tubescreamer to give a slight boost for lead.

That's a good point about the pick-up setting.

I plan on just using my modal ear and hope to come up with some tasty phrases.

Tasty is the name of the game..... forget shredding..... forget 2 string bends... they sound like country most of the time....

When I play smooth jazz....I play whatever I think the songs wants me to play.

 listen to my sound click tunes... Slow Dance In the rain,   A memory of you,   Somewhere South of here, Lonely Girl, Sao Paulo nights, and some of the others to see what I played on these tunes.

Have fun... smooth jazz is one of my favorite things to play....

turn the tone knob down to about 6.... volume almost full... 8 or 9..... neck pickup for a fatter sound.... set the amp clean... with just a taste of almost at but not quite overdrive..... clean is the work here..... on the neck, play with a mental attitude of light and airy..... I often take my hands totally off the neck between phrasings..... don't feel like you need to play alot..... think space in the music....  a note or two here, a little phrase there that reflects another instrument, a harmony run with the sax there...... the only time you break out is if you have a solo part... but even then, restraint is good.  Fast clean runs to show that you can play are good...BUT they must be clean.

Now... go and have fun.

For playing in the Groover Washington style ... Think Mellow Funk - Fusion !!! I tend to play it in the same style of Average White Band / Earth, Wind and Fire or the Isley Brothers interlaced with some bluesy Jazz ala Wes Montgomery

The Saxophone and Guitar trade spots often thus it's important to follow cues from the Sax and embellish on the theme or Motif. The scales most commonly used are a cross between the Penatonic when getting Funky ie Mr. Magic  as well as the Major / Minor Scales ie. Major 7th / Major 6th and Minor 9ths scales.  A lot of what happens will be improvizational

Hope this helps.