Just as a follow up to this thread for future readers. I ultimately did find a solution. Looks like I just never posted it.
While I was not able to find a suitable 18" bar to run an interchangeable chain with my 362, I was able to find a more suitable bar for it than it came with. The 20" bar was just way too much for the 455 rancher. Especially with 3/8 chain. However, I didn't want to change the chain pitch so that I could at least use the same file as with my stihl. So I went down to a 16" bar and couldn't be happier with it.
The bar I put on it is an Oregon 160SLHK095 and I run Stihl 33RS60 chain and it works perfectly. Pulls it great. like a new saw. it was an absolute turd with the 20" set up.
I definitely believe that most people run too much bar/chain on their saws (and that most saws come with bars that longer than ideal for them).
