How many items should you flip at once.

Or does it not matter. Should flipping be very continuous meaning one flip after another or...? I have a 100m stack to work with.

A few would be a good idea so that you're not placing all of your wealth into one item and also it gives you the chance to work with different types of items in terms of both item type and merchanting type (active/inactive, high price-low limit/low price-high limit, etc).