Are you using a RCBS Sidewinder?
I use a small Thumler Tumber Model A-R1 rated for three pounds (of rocks), so my capacity may be a little less. I can't quite remember the weight of the pins, but I think its in the range of 12 to 14 ounces. I'll try to remember to weigh my pins when I get home tonight.
My standard mix is roughly a pound of brass, the stainless pins, enough water to cover the brass 1/4" to 1/2", a small amount of Great Value dish soap and 3 to 4 pinches of Lemishine. Seal and tumble for one hour for simple cleaning or 1-1/2 to 2 hours for super clean and shine.
Over the past 4 years, I've seen many formulas for the large capacity 15# Thumlers; however, many of them are using 5 pounds of pins and 8 pounds of water, leaving room for only 2 pounds of brass. Seemed like overkill on the pins, so I started out trying a much smaller amount of pins and it’s worked for my setup. I also noted that many of those folks are tumbling for 4 to 6 hours; whereas, I normally set my timer for 90 minutes.
You definitely should deprime the cases before you tumble. This allows the pins to clean the primer pockets. I don’t like running dirty, sandy, soot laden case into my sizing dies, so I deprime using either a Lee Universal Depriming die or my drill press (my choice for decapping pistol brass).
My current small capacity setup is good for around 150 9mm, 100 40S&W or 80 .45ACP.
A lack of planning on your part does not necessarily constitute an emergency on my part.