Good on you for trying and doing stuff/learning.
The circle should go through the centre of the stud/hole so just set a compass to 2.25 inches and draw a circle?
Looks like you already did that.
Yeah I was being silly and had the bolts on the coil pack while it was off (changing spark plug).
And people say RB20DET are crap motors . They're great little motors .
I accidentally dropped a coil pack bolt into the cylinder (didn't know, thought it fell down the side of the engine) on my old R32. The RB20DET spat it out without a fuss, took out the standard turbo exhaust wheel though.