150 quart for a processed and packaged small/medium bull is about right.Four smaller coolers (50 Quart)would be about right considering the less efficient packingthis alsodepends how efficient your dressing job was and how much meat you discard as undesirale.

Igloo (best)or Coleman (cheaper but okay)5 Day Rated Coolers are my choice for everything nowadays.

If using the dry ice to "sharp freeze" warm meat, then allow 1 pound dry ice to 2.5 pounds elk meat, ifthe meatis very cold or semi frozen then 1 pound dry ice to 4 pounds meat. Especially if doing warm meat, then use pieces of cardboard with one inch holes (like apple boxes & others) and leave 3/4" to 1" around the outside edges (don't cut them tight to fit) and put cardboard between each layer of meat. This seperates the layers yet still lets the cold migrate evenly to the spots furthest from the dry ice. Keep cardboard between dry ice and the meat packages (okay to leave the dry ice in the paper bags). It is possible to have uneven cooling/freezing without circulation "holes/gaps" especially if your meat is warm and pliable.Even with frozen meat we put at least 3 cardboard seperator layers to ensure "not-too-tight/room-to-circulate" packing-job.

Warm meat or not, we place dry ice on the top, one third the way down, and two thirds the way down. We put no dry ice in the bottom, but always have some on top so that we can check the cooler and if the top ice is gone we know we need more ASAP. This way if one mis-judges the amount of dry ice needed, then you can hip hop your way homebuying additionaldry ice as you go (Cabelas to Cabelas).

More than once after "coming down out of the hills" and going to the grocery store and buying all the dry ice and getting extra boxes with the holes in them, the wife and I have been out in the grocery store parking lot with all our packaged elk meat out of the coolers (put into shopping carts), cutting cardboard, layering meat, breaking and placing dry ice, and rebuilding out coolers. This is precious cargo and this is no time to skimp.

Taping the cooler shut isa decent idea (I'd use blue painters tape instead of duct tape though), but put at least a pin hole in the seal as the gas given off by the CO2 evaporating WILL have to find a place to go --- SPEAKING OF WHICH --- if you carry the coolers in your cab, then beware of oxygen deprivation possibilities and the the corresponding drowsiness that could be caused by the abundant CO2 coming off of the coolers --- VENTILATE.