How might you develop your sense of timing?

If you still feel you need some rhythm reference, try to tap your foot quietly or gently move your head just to feel the tempo better. You have probably seen many professional musicians do this when performing live. It helps you keep a sense of accurate timing even when you aren't playing frequent notes.

Explanation:

wait i don't understand this, but my guess is that this is a trick question.

it seems to me that yes they solo on the chord changes.  coltrane for sure solos on the chord changes. instead of changing scales, they use a different method over the chord changes. this melody is very  unique but may often times even be considered simple, which is quite common in this modal  type. for example, there are changes from the key of minor to major in this piece, which makes it  unique in its own way.