Hey there,
maybe these two links can help you clarify some questions:
10 Best Practices for Designing NLU Training Data
Question 1: According to my first link huge and noisy lookup tables can hurt performance.
Question 2: I don’t think there is a total number for how many lookup table entries should be in your training data examples. I think it’s always good practice to have a balanced amount of examples.
I hope this helps you a little bit.
Regards, Tristan