I BWB in my stockpots, so for me a "load" is what fits. I use smaller pots if I have a smaller load, sometimes as little as four 1/2 pints. I put in jars so the fit and don't have enough room to fall over. They move around in the canner so even if you space them out carefully, they won't be that way when you open it up. If you have a rack with holding spots, you can keep them apart, but with just a bottom rack, if there is room for them to crowd together and then have room for one to tip over, seems like that is just what they do. I now always add jars with water (no lid) to fill any "empty" spaces if I don't have a full load. Like Digdirt said, for PC you need a pot big enough to hold 4 quart jars - usually about 10 qt liquid capacity.

The chipper/shredder distinction has more to do with the input than the output. Most homeowner machines have two inputs. The shredder input is for soft stuff or small stuff (garden refuse, leaves, twigs) and leads to a chamber where the material can bounce around against the blades or flails until it's all processed. The chipper input is for branches, from maybe 3/4" to whatever will fit, and takes the form of a tube that leads directly to the blades. I've never owned one (only rented), but flail-type machines have screens through which the material passes as it's processed. I believe some of these machines have interchangeable screens that give you some control over the size of the output. I can't tell you how well that works. As for the reduction ratio, it has to do with the reduction of volume of the material, not the size of the stuff that comes out. For example, if a unit gives a reduction ratio of 10:1, you could expect a cubic foot of leaves to reduce to about three quarts at the output. The exact ratio, obviously, would depend on the nature of the material and how volume was measured at the input. You might consider renting a representative machine for a day to see whether it does what you want. Or see if you can buy something used on the cheap so you don't lose a lot if you're dissatisfied and have to sell it. Any good chipper/shredder tends to be pretty expensive new.

If you are referring to the overflow pipe when you say "16 inches", that could vary by manufacturer and tub model. According to some the standard height for tub valves is 28" above the floor with the spout being located below that. Install the shower switch valve at the same height as the tub valves as shown HERE. The shower head should be 72-78 inches above the floor. All of this can vary depending on the height of the user, or personal preference and aesthetics. Valves for a shower only are set at 48 inches above the floor.

Al has posted many times about pruning. Here is one thread that he started a while ago: https://www.gardenweb.com/discussions/5185228/pruning-basics-q-and-a-format#n=70 Generally I do not put anything on the cut end especially if they are actively growing. They will heal themselves. If they are dormant then I put a paste meant for it. Available from bonsai supplies. But you can just put a dab of elmers glue (the kind meant for all weather). Insects cannot get in easily but can get infected by fungus or bacteria. Your cut does not look bad. Definitely a sharp pruner is essential. Cleaner the cut the faster it will heal.