Heat Map Assistance

Hello,

I am in the process of creating a heat map and have encountered the following two issues:

1) My heat map contains bubbles on it. There is a number assigned to each bubble. How do I place the number (ie. data label) inside the bubble as opposed to outside the bubble?

2) Currently my heat map is scaled from 0 to 6 (on each axis) in one point increments. How would I be able to scale my heat map in 0.5 point increments?

Thank you in advance!