While testing the different Shields Betweenlands provides. You might want to use the Dentrothyst Shields for their ability to block incomming splash infusions (including the vanilla splash potions). However I have come to notice that these shields do not block the splash effects depending on an angle of ~90° like the other Shields do. Which means you can block a splash potion from any angle, like illustrated bellow:

Thus, I suggest to adjust the angle which protects from the infusions/potions to match the players default field of view. Which is around 90° if I remember.

That's intentional. The shield already has such a niche function, so I think it's fair that it gets a greater blocking area for splash potions ;)