I don't know if adjusting pH would be necessary. JLAP used to put diluted terracycle directly into the pitchers, and I sometimes put Oscomote pellets (which have micro/macro IIRC) directly into the pitchers. If you try that, you should be careful not to do it too often. I'd say wait at least a week, preferably more between feeding pitchers on the same plant. Also, you should wait at least a week before feeding a pitcher the first time after it opens up. I don't feed the same pitcher w/ Osmocote more than once.

As I've said before, neps take up nutrients best in this order: pitchers > roots > leaves.