Epoxy cures by an exothermic reaction. West's slow is probably a bit faster than what you've used previously. I would never mix such a large batch unless I could immediately pour it onto a project- such as wetting out glass. You can extend the pot life by increasing surface area using wide- bottomed containers such as a quart pail or a roller tray. More waste with that approach. Doing large projects in the cool mornings (although increasing temps cause wood substrates to outgas which makes the epoxy have bubbles) or in the cool of the evening (beware of dew point problems causing cloudy finish, and greatly increasing the blush).

Thanks, you've given me some ideas to work with.

A pint is a LOT of epoxy. My mixes are less than that, even when wetting out glass, and if the ambient temp is 80 or higher I switch to 209 "tropic" hardener - careful 209 hasa a different mix ratio. As nemochad said, with a batch that large you need to squirt, mix, and pour - no beer or coffee breaks. 

I'm learning, I used a much more reasonable amount today and I had a considerably longer working time.