Hi Eric,
Yes, I use Howes and Biobor Jr.  I didn’t think Howes did anything to prevent or kill microorganisms.  I haven’t been able to confirm any increase in fuel efficiency with Howes, but I do think my exhaust ”mustache” on the port hull isn’t quite as bad as it used to be.  What I’ve been doing seems to be working well, but if I start finding dirty fuel when I get to the Pacific, I may add a system like you have on Kimberlite.
Kent
SM 243
Kristy