The thermostat bolts are a pain. I remember using a T40 driver bit, a 2" extension on a 3/8 rachet. Pushing down very hard on the top of the ratchet, getting a very good purchase on the T40 head, I lightly tapped the end of the ratchet with a hammer (improvised impact wrench?) until the head moved just 1 mm. Then it came out easily. You don't want to strip the T40 head. Volvo changed the T40 to a 10mm bolt later on.

Dropping the cam is no big deal :>) I am not sure why the VVT cone gets in the way in the removal/install process, but you should be OK, so long as the 3 bolts are put back in the same position they were in before. The bolt holes are not round, so be careful.

Try not to break off the exhaust manifold bolts, then things get messy.

When you get the head off, you will notice 2 groves in each piston head. That is how much room these interference engines have for valve clearance. The grooves are there by design, not from valves hitting them.

You are doing great so far!
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My back feels better when I sit in a Volvo seat