Rollin' Rhumba V1
Great introduction to 3rd position but I'd like to switch the jam track up a bit by singing two choruses, playing accompaniment for three choruses as if another instrument was soloing, plus taking two of the choruses in the middle and making them my solo. The problem is the solo is in 3rd position but I only know how to accompany a rhumba in 2nd position. Is there somewhere on the site I can learn an easy 3rd position accompaniment so I don't have to switch harmonicas during the song?
Well done, you got it! Play the 5+ octave for the V7 Chord, it's the most common choice in 3rd Position.
Both are good options, but you can play the C#... it's the same note as Db. So the arpeggio is 3" 4' 5+. This is not too common, so this is why holding the 5+ or 2+ (or both for the octave) is most common. The 3" held doesn't sound to great, so we tend to avoid it.
You got it, well done.
To simply answer your question, no, there is no material on that. When someone starts to improvising (including accompaniment) in 3rd Position they're an advanced player, generally have completed the Tongue Blocking and Bending Lesson, as we all as the Music Theory and Accompaniment. They then use the skills they've developed in 2nd Position and translate them to other positions. With this said, you don't have to wait for this, you'll just apply the same logic you're apply down the road, with a more simple line, like you requested...
Here's how you do it...
Analyze what you play in a simple accompaniment in 2nd Position. For example, if you play the Charleston Rhythm on the 2 draw for the I7 Chord, then you're playing the root of the chord (G of the G B D F Chord). Translating this to 3rd Position you're now in the Key of D, so the I Chord is D F# A C. Play the D (the root note... apples for apples), so this would give you an option of 1, 4 or 8 draw. Do this for the rest of the progression. To help out here are the chords in 2nd Position and 3rd Position.
2nd Position
I7 = G B D F
IV7 = C E G Bb
V7 = D F# A C
3rd Position
I7 = D F# A C
IV7 = G B D F
V7 = A C# E G