I wish I could help you on the mechanical parts, but I'm not knowledgeable enough yet, in those areas.
One thing I can help you with is the tank size. On CRXcommunity, they clearly state that the HF holds 10.6 Gallons. It's in a popular thread on the differences of the CRXs.
Source I'm sure if that was incorrect, someone would have said something!
Keeping the gallons on the gauge lower is a safer choice though. I ended up doing that with RAVadoodle after running out of fuel with 0.7 gallons left according to the gauge. I don't top off, so it's never going to be totally full.
It was good to hear an update!
