Third position
Your advice on using second position licks over the IV chord in third position has been a real eye opener - I hadn't made that connection between the different positions before. It's definitely helping my playing.
Apologies if you've already answered the following questions in the third position study songs, but I haven't got to them yet - I'm working on My Blues at the moment. The questions: in third position, what position are you in over the V chord and which holes are 'safe' ones to emphasise or avoid? Secondly, when I play second position licks over the IV chord, is it okay to play the 3 draw unbent or should I avoid that?
1) In 3rd Position the V Chord is 4th Position. Since there are VERY few examples (can't even think of one right now) it does you no good to think this way. The key in the chord... A C# E G (relative to a C Harmonica). So, the notes below will work...
(1') 2+ 2/3" 3" (4') 5+ 6+ 6 9+ 10
I placed the C# notes in parenthesis because they can be difficult to play and make sound good. I've been using the note sequence 3" 4+ 5+ 6+ lately and it sounds nice.
2) 3 unbent (B) is a nasty note on the IV7 Chord... it conflicts with the B-flat (flat-7th) of the IV7 Chord. If you're repeating a phrase from the I7 Chord (such as the AAA or AAB Chorus Form) it can work... but is still very agressive sounding and it tends to be a better choice to play the 3'.
Good questions... you're getting quite advanced in your thinking!