I'm not talking about the very best but I would like a improvement on a smoother ride I can feel.
All of us that weigh under 180 lbs NEVER ride 2 up with no tour packs on the bike. Like a RK and SG.
I called Progressive Tech 2 times over the last 2 weeks I got 2 different guys Frank and Brian
I told them I would like a 12" shock, I'm short.
He said the 12" 412 with standard spring would give a much smoother ride.
He said if I was a real heavy guy or ride 2 up the 412 might not work but I should be fine.
I said I had 12" 412 on my last Sportster and I felt they was to stiff.
He said well then maybe you won't like the 412 but, the geometry of the swing arm on a Road King should give a smoother ride then a Sportster.
He said I get this same call over and over every day and that I would be surprised how many call back and tell them how much better the 412 are over the stock Harley shocks. I said is that including the stock air shocks, he said yes.
So my self I still need to here it from some one that has them on a RK or SG because I find this hard to believe a $200 shock would ride smoother then the stock air shock, but the stock shocks do suck.

 

I'm 150 and ride a roadglide custom. Recently put on progressive 440s with the standard springs and love them. Great solo and with the wife on back.

 

You might try giving Bitchin Baggers a call and see what they have to say. They'll take your shocks (or start with a pair they have) and customize them to you after asking you a series of questions about how and where you ride.

http://bitchinbaggers.com/

I'm 5'6" and weight 145 on a good day. They started with a pair of HD low profile shocks and shortened another 3/4" if I remember correctly and I love them. Rides just a bit stiffer than stock but still good.

 

11 Streetglide, stock shocks are truly junk. Put the 412 with standard springs and the ride is like night and day. Only issue is two up loaded we bottom at sharp over-under crossings once and a while with a full preload. I am 190, wife is probably 130. For the money they were a great mod, I am afraid the heavy duty springs will be way to stiff.
Looking into 940's, Ohlins, and a Harley parts guy told me about Works Performance which I will call this week. Hope this helps.

 

Well I have the ohlins 3-3
2010 ultra detach tour pak and I weight 165
At first they were way to stiff
Howard sent me some different springs and ow with a little adjust
they are great!!!
Now today I put the wife on the bike, tour pak, and set the sag at 1 inch
did a 30 mile trip
This Is a OMG difference

Also me solo set the sag at 1 inch its 1 inch lower than stock when sitting on the bke!!