Understanding my combi-boiler

I've just moved into a new flat which has a combi-boiler taking cold water in at mains pressure, and I'm trying to understand how it works. Specifically, I'm trying to understand how I can get maximum water pressure to my shower.

My questions are:

1. There are effectively two temperature controls for the water supply to my shower: the shower's control, and the boiler's control. Now, I imagine that the shower's cold water comes straight from the mains at mains pressure, whereas the shower's hot water comes from the boiler at a lower pressure. So to get the highest shower pressure, I would want the most amount of the cold water, and the least amount of the hot water. To achieve this, I should set the boiler to its maximum temperature, and the shower's temperature control to only let in a small amount of hot water. Does this make me sense? Or will the shower pressure be the same for any combination of boiler / shower controls?

2. The combi-boiler has a pressure dial, with instructions on how to increase the pressure. Is this representing the water pressure for the central heating, or for the hot water supply to my shower, or for both? And will increasing this water pressure then result in higher pressure to my shower?

Thanks!