I'm a little late to this party, but I have a few comments.
First off, rather than guessing at how much yeast is "enough," get comfortable using the
Mr. Malty calculator.
Secondly, as mentioned, temperature control is critical, especially in those first few days. As you've now realized, you fermented the pumpkin ale much too hot, and it likely has an abundance of harsh fusel alcohols. Those will not age out. There is no way to remove them once they're there. They will not go away with time. More yeast will do nothing but waste yeast. Take it as a lesson learned and use the swamp cooler technique on future brews.
Thirdly, don't add yeast nutrient to your wort. All-grain worts already contains all the nutrients yeast need. Use your yeast nutrient in your starters.
Fourthly, look into making starters.
It's a great way to build up the optimal amount of yeast from a single vial, and save money on yeast.
Finally, rocking the carboy on your knees is one way to aerate your wort, but it sounds quite dangerous, to me. I use a de-gassing rod (brand name is "Fizz-X") on a drill to work up a good froth before pitching the yeast. The ideal solution is to add oxygen directly with an oxygen tank and a (sanitized) aeration stone.
Good luck with the Scottish Ale brew, let us know how it turns out. Keep that temperature around 65° F!
