I used two teaspoons of Fleischmann's* bread machine yeast that comes in a jar which I keep in my fridge. The bread flour is kept in my freezer so I warmed it up by microwaving the amount required for about 40 seconds on 30% power, then stirred it around.
By the way, be careful the way you add the ingredients to the bread machine - mine requires the liquid to go in the bread pan first. The yeast needs to be on top of all the dry ingredients - probably away from the salt.
I find a digital scale of tremendous help when dividing the dough. Each bialy took a little over 100 grams of dough
*I'm very impressed with the Spell Check in Firefox. It underlined Fleischman's because I left out one n! Don't you just love technology?