Question on yeast temp and amount

Just pitched a vial of yeast for a batch of an IPA (9.9lbs LME, 3.5lbs specialty grains steeped, OG 1.080). The yeast is WLP001 California Ale Yeast that came in a vial that I pitched directly into the wart after it came down to 75 degrees. The bottles says to use a starter if the OG is above 1.070. Should I add another vial to increase yeast cell count? Is there a point its too late to do that?

Also, the temperature range listed is 68-73 degrees. First in general, are temperatures listed for AMBIENT temp or actual wart temp? Cause I know that the actual wart may be 5-10 degrees above ambient due to the exothermic nature of fermentation.

With that in mind, would it be better to move the fermenter to a place where the temperature is CONSISTENTLY 64 degrees (4 degrees cooler) or a place where the temperature could fluctuate from 68-75 degrees throughout the day?

I make a starter for anything over 1.045, assuming a five gallon batch.

It certainly couldn't hurt to pitch a second one if you have it on hand. It's not too late.

The temperature refers to the temperature of the wort. Regardless, it is best to keep your wort from making rapid temperature swings.

With a beer that big, the temp might get closer to the 10 degree bump than 5...
I'd try to put it where ambient is 60 if possible - perhaps a bathtub filled with cool water? (if you don't have a fermentation chamber/cooling system)

I just measured some temps around the house. The basement is 62 degrees while the upstairs is 72 degrees. The range is listed as 68-73 so I went ahead with the upstairs which was in the range. Thoughts on that?

Once fermenation gets going, it'll probably get at least 5-7 degrees warmer than ambient. If you think that you'll like the results of WLP001 at that temperature range (it may be quite fruity) then it's fine. I like that yeast at about 63 degrees (wort temperature).

My last brew was right at the upper edge of the temp range and it was a bit too fruity for my tastes and the style of beer (ESB). Based on everyone's advice, I decided to move it to the cooler environment.

Based on temperature my understanding with temps are this. Higher temps = fruity/esters. Lower temps = slower fermentation. Anything about off flavors?

With temperature understood, any recommendations as far as the amount of yeast? I may be able to make a trip out to the LHBS tomorrow and get some more to pitch. Its been fermenting now for about 24 hours and Im just starting to get some activity (1 bubble ever minute or so out the airlock).