I would pronounce Luis as lew-eece not Lewis.
I prefer the Louis spelling as well, people will get used to the pronunciation, lots of people pronounce names differently than whats traditional.
I agree. I would pronounce Luis more like Louise than Lewis, if that makes sense...

You can always just tell people how to pronounce his name. My name is candice, but it is pronounced can-dis, not can-dice, or can-dace, or can-darce. My mother simply corrected people when they pronounced it wrong and it didn't take long for people to catch on.