[DailyDriver]

If the engine is in the car then I would remove the spark plugs and very gently and slowly back it up to the original "Safe" position. With the plugs out the engine should move very freely and with enough caution you should be able to feel any obstructions pretty early. Slow and with great caution. If anything gets bent the engine is coming out. There are probably others who would recommend otherwise but this is probably what I would try first.

 

[DailyDriver]

Also, I would recommend changing out the original tensioner bolts for the replacements from ARP... available not directly from ARP but from JAE.

 

[DailyDriver]

We've all been there. Most of us admit it. I think your plan will work. If you only slipped a tooth or two and only rotated the crank about 1/4 turn I believe you should be able to see the alignment hole in the offending cam before you fully return to the Safe position. Return in small increments and you may be able to spot the hole as it appears before fully returning.

 

[DailyDriver]

The numbers you got for a cold test would seem to point that the valves are okay. Perhaps checking if you can narrow where the ticking is coming from a bit more precisely, like with a stethoscope or something, it could help narrow the problem down to a specific cylinder. In fact, I don't recall seeing a description of exactly where the ticking is coming from.

I have had a valve spring fail. I don't recall any ticking from it but don't know if it broke while driving or at idle. It did bend just one valve. Perhaps you have a failed spring? Just a shot.

Have you let it idle until it warms up yet? Perhaps record the sound and post an audio clip. Sometimes the sounds can best be identified when heard and recognized.

 

[DailyDriver]

At eight years you were wise to change the belts. Could have gone more... or not. Pretty cheap insurance and the knowledge you gained about your engine is priceless. Lacking truly certified Lotus training on your engine any information you are getting on here is from people who learned just like you, some with professional mechanic experience and some (like me) without. Just keep learning and you'll have the answer for someone else too.