Wolfster,

You are mostly talking money management, which is the most important aspect to investing, far more important than stock picking, IMHO. Most importantly, you have to stay within your comfort zone. If your investments are keeping you awake at night, you're doing something wrong. I never have more than 10% of my portfolio in one stock. You have to chose your own level, but I would strongly recommend 20% as an absolute maximum. If you happen to have a large position in a stock that is doing well, don't be afraid to sell small parts of it, to keep the position under your limit. You can keep doing this all the way up. I know you are supposed to let your winners run, but taking a little off the table once in a while is prudent - remember, pigs ultimately get slaughtered.

Regarding buying - for me, it all depends on the technical configuration. If it looks like a good entry point, I buy all at once. If it's run up a bit, I often buy half and try to buy the other half on a pullback.

Right now 90% of my portfolio is in this speculative stuff. Why? Because it's working - at some point it will stop, then I will scramble to get out.