Big bubbles like that are looked upon as very favorable up here in Montreal. Pizza is more european here, and big bubbls are nice. There's
nothing wrong with them at all.
I could never achieve these bubbles before I put my oven at the highest setting..... so when I did and finally go the bubbles, I realized
I was getting better.
Now, for your "problem" ..... when I was in pastry school we used a little gadget called a "docker" ... the pizza industry uses this also,
so you can quickly roll this over your dough and never get the bubbles you got..... or you could use a fork and do this also, although the fork
doesn't seem to work as well. The docker has large needles on it, and really makes a large hole, and works well,, but these can set you back a few dollars.
As for the amount of yeast you used, it has less to do with the amount you used, and more to a nice hot oven. However, try cutting down your
yeast and doing it that way.... hey at least you will save on yeast
it's not that expensive, but still is.
How many times have you done your pizza with the recipe that had the big bubbles ? .... has this only happened once ? or has it happened on
all trials with this recipe ?
anyway that's about it.
Oh, I guess on a technical point: The very large air bubbles are created by moisture that is trapped inside that "air pocket" .... the sudden burst
of heat, expands those air pockets into the bubbles you see, it's a combo of the yeast first creating that pocket, and then the moisture in that pocket and on the lining of the inside of the dough bubble.
anyway hope that helps.