Head Bolt Torque and re-torque and Crank bolt

[Michael2007Mini]

Hello, I have an R56/N12 6spd (non-S) that I've been working on... again. I bent the valves on my head again since my crank bolt backed itself out while I was driving. Not a good thing as it bent all 8 exhaust valves. Do the $math on that cost.
My question is about head bolt torque. Once I torque the bolts down, should I re-torque them after the a short break in period?
The reason why I'm asking is that the bolts where a bit difficult to remove from the first time I worked on the car. This time, the bolts came off a bit too easily. If you've removed a bolt like this before you know that feeling when it breaks loose and the sound it makes. This time, no noise and it felt too easy as if I hadn't even torqued the bolt down at all.
--So...
Should I apply some lock-tite or some other form of "sealant" to the bolts so they don't feel loose or loosen up?
Should I re-torque them after some period of time? How long?
Do I need to prepare the engine bolt holes with anything prior to installing the bolts?
---
I did have a manual and it did not say anything about prepping or re-torque. If you have a manual and it says something about this, could you please respond with the verbiage from your manual.
---One final question:
The crank bolt backed itself out, maybe I did not get the torque correct, but one thing about it was there was no washer. The original bolt that I removed did have a washer. I have noticed that no washer is sold with the replacement crank bolt on PelicanParts. Would anyone be able to help me pick out the correct washer for that bolt and maybe enlighten me as to why they think the bolt backed itself out? Should I have used lock-tite on this bolt too and should I with the next installation?
--Thanks,
Mike

[Luccia at Pelican Parts]

Are you using the Bentley Manual? Mini Cooper, Cooper S, and Clubman (R55/R56/R57) - Books & Technical Documentation - Page 1

That's the manual I'd recommend you'd have if you don't. Follow instructions in it. We can get you the correct washer, please give our MINI parts specialist a shout at 888.280.7799. You should be able to ask additional questions about your install to them as well.