I was unavoidably a bit vague when I used the expression "on the cool side" because it depends where you live and the temperature where you are making the dough. Where I live in Texas, and especially in the hot summers, if I am trying to achieve a finished dough temperature of, say, 70-75 degrees F, I will usually need to use water that is cold right out of the refrigerator. If I lived in Canada in the winter, I would have to warm up the water to get the same finished dough temperature. There are several factors that are involved in achieving a particular finished dough temperature: the room temperature, the flour temperature, the frictional heat added by the mixer (which varies from one mixer brand and style to another), mixer attachments used, mixer speed(s), mixer time(s), dough batch sizes, whether preferments are used, whether autolyse and similar rest periods are used, and whether other delays are introduced intentionally or unintentionally into the dough making process.
What some pizza operators do is to calculate the water temperature needed to achieve a finished dough temperature. In some cases, they use charts to do this. You can read about this procedure at Reply 41 at http://www.pizzamaking.com/forum/index.php/topic,8341.msg73486/topicseen.html#msg73486
(including the link to the Lehmann article). I have found that the methods described in Reply 41 and in the Lehmann article seem to work best for a straight dough, and for doughs that are pretty much the same from batch to batch, as is usually the case in a commercial setting. It is tougher in a home setting where we change the variables much more often.
With respect to the blisters, I personally like them. To the extent that they are produced because of long fermentation, they are usually a good sign that the crust will have good flavors and aromas, because of the multitude of fermentation byproducts that are produced during long fermentation and that are responsible for those effects.
As between changing the amount of yeast and controlling the water temperature, my first preference is to adjust the water temperature to get the desired finished dough temperature (75-80 degrees F when a standard home refrigerator is to be used). In a commercial setting, that is the usual method, especially if low skilled labor is used to make the dough. However, in a home setting, in addition to adjusting water temperature, I will often use different amounts of yeast for summer and winter applications.