Ok , here's the deal with the block not draining evenly. Say the block is full of water after a day at the lake. If you open the left block drain it will drain the block down to the mid section ( roughly around where the water pump is mounted ) and the left side of the block around the cylinders. Then if you open the right block drain it will only drain the lower section of the block on the right side. (it already drained the top section through the first drain opened).
Here's a little trick everyone needs to know. The left side of the engine ( the one with the oil filter on it) if you disconnect the lower hose on the engine oil cooler, not only will it drain the oil cooler but that hose goes directly to the left side block drain. It will drain the left side for you and you don't have to try to snake a 10MM wobble extension up in there to try to open it. NO more rounded off or seized drain plugs!!! You do still need to open the right side block drain. I highly recommend you coat the threads of that drain with antiseize every time you remove it. Trust me your winterizing will go much faster and easier.