Add switches to Stack

We have 2 old Cisco 3750 stacked and we need to add 2 new switches in the stack because we ran out of ports.

The LAN switches are connected with stacking cables. They act as one single switch and share their configuration and a common management IP address. One switch has the role of stack master and the other one is backup or member. The configuration is stored on both switches. If the master should fail then the member becomes the new master.

I have 2 2960 S switches available, can I add them to my current stack? Are the models supported?

Once I connect them with stack cables, what configuration needs to be done, is it all covered here: https://vmguru.com/2010/03/hot-adding-or-removing-a-cisco-3750-from-a-stack/ or anything else to do?

Cheers