MST configuration N4064F

Hi Team/Support,

I need your help on this production environment please:

The current topology is as follows:

SW1 is connected to SW2, and SW2 is connected to SW3.
All the connection are the point-to-point cross connection.

We've recently established a new point-to-point link between SW3 and SW1.
The interface connecting SW1 to SW3 is currently shut down.

Below is the current MST configuration on our SW1, SW2 and SW3 core switches which I think it has all the VLANs by default.

show spanning-tree mst-configuration

Name: MAC address
Revision: 0

Instance    VLAN Mapped
----------  -----------------------------------------------
0           1, 3, 100, 200, 300, 500

Only VLANs 3 and 300 are allowed to pass through the point-to-point links between these three core Dell switches.

Given this setup, how should I configure MST for these interfaces? Should I use a single current region or create a new region and use multiple regions?
If I configure a new instance within the current default region, will there be VLAN overlap between the instances?

Could you please assist with the best approach?

Thank you

Regards

SF