Vital Wheat Gluten is a good addition to a bread formula and yes, you can use
it with regular flour in place of bread flour.
Usual usage rate is about 0.01-0.02 lb of Vital Wheat Gluten to 1 lb of flour
but it varies depending on the type of bread you're making and the amount of
dough development you're looking for. Use a lot if you're planning to make
something like hearth breads or bagels which require the product hold it's
own shape. Also use higher levels in a formula that has whole wheat flour or
other grains or fruits to "dilute" the flour. You have to experiment a bit
to get the right level for the formula you're working with.