Now that I reread my own question, I noticed that I didn't really make clear what I wanted to know:

Let's say you have limited space in your pack but you want to add something to treat massive bleedings. Would you pick "chemical" or "regular"?

But I don't want to highjack this thread, so back on topic:

Hikermon, in first aid class (a course especially for basic life support in car accidents) we learned this to apply pressure: Put the dressing of your bandage on the wound, roll some of the gauze around and then put another (still wrapped) bandage on top of the dressing. Then wrap tightly until it stops bleeding, maybe even by adding another wrapped bandage on top of the first one.
Actually, you have to roll in a special way to better not completely restrict the bloodflow of the extremity (if the wound is on the upper arm, for example).