Personally, I like to keep 3 lenses. Clear, amber/yellow, and a mirror/smoke. Clear is great indoors and depending on how well you can see better for yellow paint. I honestly don't like playing a tourney unless I have a clear lens in case I start doubting my eyesight which has cost my team a few points where I couldn't tell the difference between stained fingers and a yellow hit.
I like smoke/mirror for bright days since it'll darken it quite a bit and you won't have to worry about sun glare. If you're going to be playing woodsball I'd suggest a yellow/amber lens or just a clear lens though.
You may call it fat, I call it bounce padding.