To me rear stock air shocks ( on a 07 flhr) ride a little too harsh , other than adjusting air pressure, would changing the shock oil to a lighter weight make it ride any smoother...??from what iv 'e been able to figure out 5wt, is stock wt.

 

I changed my shock oil with a 15 weight Castrol fork oil they are firm solo and just right with a passenger with no bottoming out. Your shocks sound as they might need a heavy oil rather than a lighter oil because the heavy oil will make compression and dampening work better taking away that harshness when bottoming out. I read most people use a 7 or 10 weight oil

 

Yup, the oil that in them is about 5 weight, we just changed out the oil in one set with 10wt and the difference in damping is amazing. He's using less air now and has a much better ride without bottoming out.

 

Here is a link to a thread I posted about changing my shock oil. It contains links the the threads where I got my information. You will want to put heaver oil in the shocks not lighter. I put 10wt oil in mine and I'm extremely happy with the results.