The best way to answer your question is to go to the engine
manufacturer or distributor and ask what the front end PTO limits are. Then you will know the answer to your question. Of course that's easy to say but sometimes difficult to actually do.
Most engines have limitations to: 1. the amount of power that can be pulled from the front end 2. The direction of pull 3. The amount of pulley overhang allowed.
This is normally expressed in a diagram that looks sort of similar to a sailing polar diagram. Theses diagrams typically show that lower h.p. engines are more sensitive to power and pull direction than larger engines, so it is something that you should be aware of.
In the event that you can't find any definitive information, probably the safest thing to do is to move the raw water
pump and balance the loads.