Flexwatt; 11" or 4"?

I'm planning a snake rack, however the flexwatt doesn't have the exact size I need. From what I've read, you want to have it under 25% - 33% of the tub. My tubs are 23" from front to back, which would put 33% at 7.66" and 25% at 5.75". I was hoping to cover closer to .33%, so, umm, should I use the 11" tape and cover about 48%, should I use 4" and cover 18% or should I go the icky route and use two strips of 4" to cover 34% of the tubs and use more outlets (another thermostat)? Thanks in advance for any help or advice. :)

My tubs are about 23" as well, and 4" has worked fine for me for about 2 years now.

Im not a flexwatt expert but I put a big enough piece where my snakes can cover its whole belly. As much as balls ball up. I think a 4inch per is good imho, but thats just me. ;)

You dont need that large of an area, I have Freedom Breeder racks that are used by many professional breeders and the large tubs (CB-70's) only use 3" flexxwatt. You also have to consider if there ever is a problem and the thing gets too hot you want to have alot of cooler space they can get away from extreme heat.
Hope this is helpful.

Thanks a bunch guys, I just placed an order for 4" tape and connections.

i am using 11" flex on my snake rack and everything is fine...i think its a larger, more uniform area of heat for my tubs.... as long as you keep the temps right, it doesnt matter too much what width heat tape you use.