Let's end the year on a jam! I am guessing that this track was recorded during the same session as "Doing It To Death," since, here in "More Peas," Brown references back to the "What do you think of... when I say, 'The key of F?'" banter. Although Brown jokingly calls Friendly Fred a "square," Fred's solo on "More Peas" is full of hip ideas.
The overall harmony on this groove is a G dominant 13th (E), however, Fred usually only plays up to the 9th (A). He's not afraid to use the #9 (Bb), especially in the first ten bars of the solo, but he will usually resolve it up to the B natural. There's also a hip chromatic passage in bar 26 where Fred outlines the G9 chord.
As for the technique of this solo, it all depends on the swung 16th-note rhythm. This rhythm is what makes this groove swing, and by accenting the swung offbeats, Fred gets funky. Try thinking of this solo as a 2-3 syncopated pattern, with a "hiccup" on beat one. Also, experiment with alternate slide positions since most of the notes can be played near the forth position.
Here's a YouTube video of Fred Wesley and The Apples, jamming somewhere in an Israeli recording studio. Notice how quickly Fred can pick out melodies on his horn. Good ear!
Recommended Reading: Hit Me Fred: Recollections of a Sideman by Fred Wesley Jr. Published by Duke University Press.