I believe someone told me that for NT players get 10% of whatever their salary is if they play in a NT game that week for merchandise boost. As for the other home grown play stuff, I'm not sure how much of a boost it gives, but like you said, trained players that you get when they are young gives you a lot of tax exemption, so they are valuable regardless.
Murray/Harris/MPJ/Grant/Jokic - 2020 NBA Champs