What Coolant Expansion Bottles You All Using

Hi All
Eventually going to put different seat unit on my bike and was wondering what replacement expansiontanks youare all using and Whats out there.
Round one , 350ml, is one already have to see if fits and square one is another I like to bolt to side of engine and is 1litre ( bit big?) It also handily has a level on the side to check coolant levels. Is a litre too big ?

 

I think standard under seat one is 500-750 ml ?

 

The Square on is just over £38 inc postage from China, on e-bay, Bless em they do some really good deals as long as your not in a hurry.Although the other one I bought took just over 10 days which I thought wasn`t bad from the Land Of The Rising Sun

 

I have to say even though I already have the round one, the square one is looking alot better now and would bolt on side of cylinders where the fairing bracket used to be