Help checking alignment of prop shaft

[BB-03_21LSV]

My Boat: '03 Sunscape LSV Vdrive, 335 Monsoon.

I've had a slight increase in vibration over the last 6 months and have the boat in the garage torn apart to fix loose fins (separate story). I have wanted to check the coupling for alignment to .003". Never tried this before. Can someone tell me if I am doing this right or wrong...

1) I completely loosened the nuts on the coupling, but did not loosen or back out the screws or touch the set screw.

2) I spun the shaft a few times and a gap opened between the brass colored shaft coupling and the steel output flange of the vdrive

3) the gap is .030", but is perfectly uniform across all 4 points between the screws. This is 10 times .003" of course , but it is very uniform

Am I checking this correctly? Or, should I be looking for .003" difference between the four checks around the coupling?

Should I have backed the screws out and removed them after removing the nuts before checking?

Should I have loosened the set screw?

If I'm doing it right I am not sure how to close the gap and keep it uniform. Is it time to panic and take it to the dealer to tighten up the .030 clearance to .003", or re-measure it correctly?

Thanks - Bruce

[BB-03_21LSV]

Was not doing it right..... did find that it was out of alignment - but all better now.