I agree with Gene and the speed also. 95% of the time I sticker mine every few hours as I saw BUT occasionally I run out of steam, dark catches me, or the unexpected (over the years have vol. as fire chief and also extracation in our rescue) and I have to finish the next chance I get. I once left some 48 hrs in hot weather BUT assumed the heat would hold it off ONLY to have to pry the slabs apart due to mold growth....NOT again for me, TOO much trouble!!
I would see if your friend/client could arrange for a quicker pick-up. Just explain the molding risk issue IF they can't and the cost IF you have to sticker which isn't normally included in sawing price. A lot of people don't understand steps and cost factors associated with most business processes and assume it's all one unit, I've learned to educate them in the cost processes of my sawing and lumbering and ask them which steps they want me to do and/or if there's some part that they'd rather save money and do themselves. Surprising i get paid sometimes to do simple things and others refuse.
Mom taught me one thing re business (I'm multi self employeed (many businesses))
"....son business is how you make your money...someone has to be hired to do the job...no one else will do it for free... charge family and friends the same as normal clients...some you'll work for and the others they just saved yourself some headache somewhere..." THANKS Mom!!!!