Stack M4300 - suggestions about design and number of stack links

Hello,

I am in the process of migrating from another vendor to Netgear M4300 family and changing the design of a small network accordingly. I have attached a diagram of what I imagine to be the optimal design.
SW 1 - Netgear M4300-24XF,
SW 2 - Netgear M4300-12X12F
SW group Access - 2 to 3 Netgear M4300-48XF
Servers and storage supports 10Gbps, multiple links, the storage is all-flash 20GB/s+;
stack 02 - netgear m4300-28G.
Core sw 1 (wing) is acting as a extend to core sw 2 ( main), and there should be another set of core sw-s to act as a failover to  the first ones.  So first picture is showing only the half.

Why do I choose this design? - all switches are given to me as a gift (the entire network in the headquarters is dismantled and I will receive a small amount of network, storage, server equipment).

Yellow links are a stack links.

Clients are capable of gigabit connection.

Core SW 1 and 2 - M4300-12X12F

Core SW 3 and 4 - M4300-24XF

 Since Storages are going to communicate only with Servers (iSCSI, NFS)  are connected to SW 3 and 4. Servers Should be connected to SW 1 and 2 if no free ports are present on SW 3 and 4. 

Internet and some other management interfaces should be connected to sw 1 and 2. (Access) Switches facing clients are going to be connected to sw 1 and 2 ( 2 stack links per sw, one to sw 1 and one to sw 2, no stack links between access SWs)

Questions:

How many stack connections should I create between:

- SWs 1 and 3 ( same as sw 2 and 4)? - 4links

- SWs 1 and 2 ? ( or should I decrease number of stack links and move them to sw 3 and 4 ) - 2links

- SWs 5 to 7 ? - 0 links

- SWs 5 to 7  to sw 1 or 2 ? 1 link  ( sw 5 will have 2 links, one to sw 1 and one to sw 2)