I have the standard bathtub with a shower, so there's enough room to move out of the direct stream.
To savesome water while shaving in the shower - I have a "modern"mix valve with no volume control - I got a valve for just before the showerhead at Home Depo. It allows me to cut the water flow as low as I want but not change the temp setting. If you go this route don;t waste your money on the push button type (about 6 bucks), go for the type that has a regular twist knob (around 10 bucks). The push button ones eventually get stuck and are impossible ot repair. I'll guess I saved the cost of the valve in hot water use reduction in under 6 months.
I use the sink in front of the mirror... Suits me well, since i have better control and manuever over my dome. I always end with a smooth dome.
When I first started shaving the head I used the sink. I got a mirror that you fill with hot water so it won't steam up and tried the shower. Wow! For me I got the biggest improvement in my shave of any single change I have tried. I love the idea of a valve to restrict flow when it isn't needed. I use a whoppin amount of hot water and it would really save some money. I do head and face both while I am in the shower.