Peter Torx

I sat down to do a leisurely conversion of an SLX 2x crankset to a 1x with a JG bikes, 32 tooth chain ring.

Imagine my surprise when I try and stick in a hex wrench and it appears to be a Torx screw I tried the two Torx heads that were in my tool kit, but both seemed a little too small. my questions are:

is this normal for the SLX cranks set?
How do I figure out the size the correctTorx head size?
And will it take the hex nuts that came with the chainring or do I have to use these Torx screws again?

by Returning2Riding