Lighting opinion wanted

I am getting a Nfab 4 tab bar and have decided to mount KC 6" long range 130 watt slimlites on the outside. On the inside I will mount driving lights but I am having a tough time deciding on 5" 55 watt or 6" 100 watt. I really like the look of the smaller lights in the middle but my main purpose here is illumination. I am just not sure how much I will gain from having the 6" versus the 5". I was thinking that I could go ahead and get the 5" and if they are not doing the job maybe put a 100 watt buld in them or put them on my ATV.