Sonic had suggested I do the 7wt Bel-Ray for more tour then sport riding. It does a good job of soaking up the bumps and not feeling too bouncy.
Yes, there are a number of stock suspension motorcycles that utilize one leg for rebound damping and the other for compression.I agree with dduelin on this. My Racetech upgrade actually converts on fork to just compression damping and the other to just rebound damping. When everything is bolted together you don't notice this. So I'm not sure that you would be able to feel a blown valve through a particular hand grip or turn.
While I agree with you about the forks working as a whole unit, I believe it would be foolish to swap rods in forks, when I cannot get what I consider the suspect damper to work correctly while on my wrench. I have bled and pumped both cartridges for 10 minutes and only the right damper works as it should. The left one will not draw or push ANY fluid (MMO, ATF, SOLVENT,etc) smoothly.When the fork is assembled it should work as an integral unit. Any damping problem with one side will affect damping as a whole and not affect steering or damping in just the left turns and not the right. Sorry, that makes no sense at all.
The reed valves inside the cartridge are pretty much impossible to blow out, they are going to work or not work, and orifices don't open and close intermittently unless there is trash blocking the orifices. An intermittent problem you describe sounds like the cartridge may not have been bled completely and had trapped air. $150 each for damping cartridges is an expensive way to throw new parts at this problem. If you think the left cartridge is causing a feeling in the left grip then install it in the right leg and see if the problems clear up on the left and move to the right side.
Then ignore the second paragraph of my post and concentrate on the first one.While I agree with you about the forks working as a whole unit, I believe it would be foolish to swap rods in forks, when I cannot get what I consider the suspect damper to work correctly while on my wrench. I have bled and pumped both cartridges for 10 minutes and only the right damper works as it should. The left one will not draw or push ANY fluid (MMO, ATF, SOLVENT,etc) smoothly.
When something does not work as it should, rather than "trying to get it to work" , I think it's a better idea to simply replace it and remove that concern. It's only money, and cheaper than risking an accident.