I wish I could. I've been hoping someone would be on that had some advice for you. Incubators can have warmer and cooler spots, but I can't see 19 days vs 23+. Not based on experience here at all, but if I were in that situation and could see them moving I think I'd move forward with making an initial pip for them...
Hoping someone else comes along soon to advise.
Should I pip it internally as well as externally ?