The tank works and I would not remove it bottom line. I would, however, remove it if I was racing and/or only haveing the bike run for a SHORT amount of time.
Given, I do only ride in the dunes of Glamis and Gordon's Well where tempatures reach over 100 degrees BUT I have proven to myself and you can take it for what its worth.
I was at camp (probably sipping on a cold one) when I looked at the coolant bottle from my seat when the bike was cool and it was empty. I said to myself "that is weird" because I changed the oil and cleaned the filter and checked the fluid the night before I left for the desert. So, I go into my camper and grab the 50/50 "mix with any other color coolant" fluid that I happen to have. I always run 50/50 coolant distalled water with water wetter in it and all the coolant is blue. Okay, so, I put the ORANGE coolant that i have into the bottle and I chill for a while eating lunch. I go out on a ride for about 2 hours with some friends. When I get back to camp I look just to make sure that the bottle is not empty and its not BUT the thing is that its ALL blue in the bottle again. Point is that all the orange coolant that I put in the bottle mixed with the blue coolant that was already in the bike, but sinse there was more blue than orange the blue it was mixed with overtook the orange.
I would not remove the coolant "overflow" bottle if I was you.