I get it. Went on a similar journey for largely the same back-related reasons. Out with the Precisions and in with the Mustangs for me too.
YMMV obvs but as someone who has always massively favoured a Precision, the JMJ for me feels and sounds like a smaller, absolutely killer, Precision. I absolutely love mine to bits and really can’t say enough good things about it.
Mine feels enough like home now that I’m properly happy with it. And I never thought I’d be ‘OK’ not largely playing Precisions.
Hope yours works out similarly well!