I am interested to hear what folks have to say, but when I use the cobra tap, I raise the tap/bottle/hose combo higher up in the air (I actually stand on a chair) for a few more feet of rise...this seems (to me, anyway) to reduce foaming/co2 loss (along with cold bottles).
I, too, use an old cheapo wing capper I got with my first kit (20 years ago)...no problems.
I don't bottle to keep beer, usually just to transport to friends or put into upcoming comps, so I wait until almost the last day to enter/last minute before I leave to bottle. I usually bottle an extra or two and open it on the competition day to see if it is still properly carbonated (and always has been).