FBM Inventory 20 units refreshed daily or 100+?

Would it be better to show 20 units or have 100+ , I refresh inventory daily and show 20 units purposely to increase impulse purchases. I have 1000’s of units on hand. I used to show 10-12 and once I started showing 20 my sales went up 30%. Should I show 100+? How does this work?