I've tried all the techniques you listed at some point or other and all had their advantages and disadvantages.
First, I always go over donating procedures with a new buddy. I even encourage practicing them during safety stops or just after blowing through whats left of our tanks. I practice switching regs on just about every dive, more about that later. One thing I've learned is that in the heat of an out of air emergency, panic in either diver can be dangerous and practicing the procedure is the difference between a minor incident and a major dive accident.
As a newly minted diver I started out with a medium length primary hose and a longer hello octo hose as I suspect most divers did. The first thing to personalize for most divers is how to attach the octo to yourself. Like many I started with just tucking the octo into a pocket and of course it would inevitably pop out and flail around or worse yet drag along the reef or sand. Then there were the mouthpiece covers with clips, several quick release clips, etc. The ones that attached to the mouthpieces occasionally pulled the mouthpiece of the reg, NOT what you want to happen during an OOA situation! Clips would sometimes let go of the reg. All of which were inconsistent and had me having to show each new buddy a new way of deploying.
The other thing I hated was the long loops of hose that stuck out from my body occasionally snagging on my environment or other divers. After getting snagged several times near wrecks, piers, ladders, and other divers I was finished with long loops of hoses extending from my body. Even after seeing pictures of myself underwater I cringed at how unsafe it all looked to me.
Next I went thru a streamlining phase in my diving. SO I went to other extreme. The so-called "two hose" diving. A medium length primary hose, and my inflator hose were the only two hoses coming out of my 1st stage. I used a transmitter for my sole pressure gauge (a TERRIBLE idea that was aborted after only a few dives, thats another story!). So with that setup I was using an inflator/secondary combo (Air2). I junked that idea after an actual OOA emergency happened to me. A nearby diver was low on air and I went to donate the reg in my mouth and I switched to my Air2. Well the reg hose not being that long made it hard for me to maneuver with the other diver so close, and that diver being a newer diver, he was having trouble maintaining neutral buoyancy. He would either sink or ascend no more than a foot or so from me and the reg would pull out of his mouth. It was really hard to maintain eye contact and communicate because if he tried to get face to face the reg would pull out his mouth since the orientation of the 2nd stage and hose would force the reg out.
That was just his issues. My issues were that it was hard for me to turn my head until I remembered to unstrap the velcro loop around corrugated inflator hose from the BC. Even then I didn't have full range of motion. Then when I went to dump air I couldn't find the hose...oh yeah it's in my mouth! I couldn't get horizontal to use my rear dump and not risk pulling the reg from my buddy mouth so I had to pull the air2 from my mouth to dump air. Managing buoyancy, keeping my buddy calm, managing a controlled ascent, monitoring remaining gas, keep myself from pulling the reg from my buddies mouth...it was just a bad experience all together. I was so relieved to just make it to the surface! Air2 went to eBay!
Finally, I went back to school as they say. I did a lot of reading and research, and no matter where I looked on the world wide web, when it came to safety and practical diving procedures, I always came back to the same place, the DIR methodology of diving. It's the concepts practiced by most wreck, technical, cave, exploration, and industrial divers. I went out and found an instructor with this type of methodology. I got trained in using a short hose and long hose configuration. For me personally, it has been the best decision I've made with regards to diving. There's a reason why advanced diving uses this form of diving. Part of my training was to practice deploying my long hose and switching regs on almost every dive. So when I had to use the skill with a fellow diver in my group, the procedure was smooth. I gave the diver the long hose that was in my mouth and switch the my short hose reg that is always around my neck, easy to find, and I could even grab it with my mouth without even using any hands. With a long 7' hose I could easily maneuver with the other diver while maintaining eye contact. I was able to maintain a little distance until the diver calmed down and then was able to lead the diver up all with no stress. We even were able to do a normal safety stop. An easy task when you're not in danger of pulling out the reg from the other divers mouth. One diver going up a foot and the other going down a foot and there's already trouble forcing.
Different strokes for different strokes, but i have become a believer in the long hose short hose setup.
all for being willing to share! 
