Let me start off by saying I'm an idiot.

Did a spark plug change and loosened a couple of bolts on the camshaft covers (1 on each side) that were easiest to reach, only to realize they weren't holding down the panels that covered the spark plugs.

I ratcheted them down best I could with a 3/8 and am going to rent a torque wrench. Between 6.5 and 8ft/lb

Anyway, the spark plug change was eventually a success (after reading the DIY and purchasing a 1/4 U-joint and a couple of extensions)

I guess I'm the worst kind of DIY.

 

How else would you learn?

Depending on the fastener and what it is holding down, I dispense with the torque wrench in favour of "just snug". Of course, you might not be so adventurous.

 

I agree with plums. If you want to feel what it's like, push on a scale until you get to 8 lbs, that's the amount of pressure to put on the wrench. It will get you in the ballpark and you'll be fine. I like to take a small wrench and just hold it by the top i.e. don't use the handle for any leverage.
take a look at the area in a week or so and see if any oil is leaking out of the valve cover (sounds like what you loosened), if so, snug them down a bit more.

It's not going to kill your Jag.