I don't know anything about Kevins product....but what i would say is 20 gallons (4 m per litre), I would consider this a very conservative guesstimation.
Taking into account you might need two applications to get it all off.
My experience is 70% 20% and 10% ...rarely it comes of in one go. I have been wrong many times before tho' 
It is very easy to get burned taking out this time of work without testing first.
Hi Chris
Although I don't bother too much with this forum any more for obvious reasons, I thought I would take the opportunity to thank you very much for the sample bottle of the remover. I tried it today on a victorian floor, roughly 160 years old that had every sealer thrown at it known to man.
I am pleased to say that, your mate in his shed at the bottom of the garden knows a thing or two about coating removers, please send him my thanks. I will be using it again.
(I hope this is NOT seen as an invitation to start a war, it is simply a thank you)