Al,I use the three finger sytem,and have no problem with full chords.
I have in the past recorded[With full chordal accompaniment without double tracking] such things as WashingtonPost,Yesterday/All my loving,DillPickle rag,PrimrosePolka,WoodlandFlowers,while keeping my finger on the finger rest,so its possible and I didnot find it uncomfortable.here is Primrose Polka
http://www.youtube.com/watch?v=boqwtu3xPzU.
when the player starts playing in e flat and a flat it gets easier because you have both those notes duplicated in different places,its fairly easy in F C G D A B FLAT,Playing full chords with three fingers.
the secret is to play the chord notes off the beat,apart from on long notes,bit like a flat picking guitarist[or 5 string banjo] playing a melody note then brushing a chord