What SAE fork oil would you suggest for a 2004 FXD with Progressive Springs?

 

I'd strongly suggest the drop in installation of a pair of Ricor Intiminators and 5 wt oil. Magic !

 

Somewhere around HDF you will find a table comparing umpteen brands of fork oil, their stated SAE and the correctly measured actual SAE. The two are rarely the same! If you go away from the H-D recommended oil, then select a well-known brand and stay with it, don't swap between brands as they cannot be trusted to be consistent. You may have to buy a bottle and try it, then swap for an alternative SAE to get the ride you prefer.

I also have used Intiminators on my Glide and liked them, but have moved on to Ohlins since.