If you notice on the cam gears--the bolt holes in the gears where the bolts hold them down--thier slotted--allowing a little bit of adjustment--I used to rum my intake cam a little advanced--seemed to help the car--any way
I think the way your going about it is right on---just to make sure I would spot the gears in two spots--one being as you said--at the cam gear location with the sheild--another would be to spot it at a couple of the bolt slot locations---that would put it back right in the same timing.

One of the main reasons I ever started doing my own work--indy put my timing belt on--ran it for a couple of years--noticed the car didn't pull right
later decided to do my own belt--intake gear was off 1 1/2 teeth--didn't cause and interference with the cams--but when I got the belt back on I found some new power---
Hope that helps