Several thoughts - I not claiming I know the answer for you. I always set my chain to never go tight and like to see around a 1/2" (1.3cm) of slack. Now, unless the crankset, bottom bracket and hub are of high quality, the chainrings and cogs don't spin perfect circles. This means the chain goes tight and loose as you pedal. The worse this is, the harder it becomes to dial in the "perfect" chain slack. (Cranksets made of road use with derailleurs are often the worst offenders because there is no incentive to make them "round". With a rear derailleur providing tension, the additional coast of manufacture gains nothing - until you decide to fo fix gear or single speed.)

Are you greasing the threads of the left side cup? (This is a cup and lockring with notches isn't it? The special tool that fits those notches will be a great asset. (Either a VAR/TA style with a ring and the appropriate prongs or a more general Park style spanner. A pin wrench to hold the cup also is a benefit. There are enough different styles that I have no idea what your setup needs but the correct tools make life far easier.)

There are those who are fans of using one of the LockTights on the threads. Phil Wood in fact says to do so with their adjustable bottom brackets. I do as Phil Wood says on their BBs but use only plenty of grease and or Teflon plumbers tape on my other BBs. (I don't always remember to use the plumbers tape, but when I do, I never regret it.)

Now, I don't skid stop. My knees wouldn't last much longer than a tire. Plus, I love the ride of really good tires and skidding gets really expensive fast.

Edit: "lightest tension that is pleasant to ride" meaning no "kick-back when you reverse pedaling direction? Too tight! Use the kick-back to teach yourself to pedal evenly. Go to slow down and feel that one nice "click" . That kick-back and learning to avoid it is one of the best smooth pedaling tools there is. (Go to the velodrome and you will see a whole lot of really skilled riders and very expensive fix gears all with a ton of chain slack. You want a touch less slack because you have road bumps and they do not but you want to be as close to what they do as you can while guaranteeing your chain stays on.