How does the new mining system actually work?

[Malidictus]

With the release of Fortuna comes a new mining system which seems to have migrated to Cetus mining, as well. To make a long story short, I don't get how it works. I mean, I get the basics - use cutter on blue dots, hold fire button, release when in box, aim for little box for better rewards.

Thing is, under the old system I could get five stars (gem icons) for every single node if I traced the outline carefully. I never did, obviously, but I could reliably get 4 - 4.5 stars. Under the new system, I do what I'm supposed to and sometimes I'll get 2.5 stars, sometimes I'll get 1, sometimes I'll get 5 stars. What gives?

Why do some nodes have three heating spots, while others have one or two? Does the new system make it impossible to get 5 stars on every node if some are just spawned with a lower quality? Because I've gotten 5 stars on a one-spot node by hitting the little box and I've gotten ~3 stars from a three-spot node.

What determines the quality of my performance? Because I seem to consistently pull fewer gems and ore from the ground now as compared to before.

[Tigerlight]

Closer to the centre of the brackets is a better cut, and the small additional brackets count as a perfect cut on that node with an extra gem drop regardless of the vein being mined.

[Malidictus]

Right, but some ore deposits will spawn with a single heating point, I'll nail it pretty much dead-centre of the brackets and still get 2.5 stars. In fact, I've so far yet to get more than 2.5 stars on any node with a single heating point. It seems to give me that much almost regardless of where I put it in the bracket.

[Tigerlight]

Nodes with less heating points are lower quality nodes. The number of points denotes that.