Let me try to answer your questions....
1) Do you absolutely need metal valve stems?
- Yes. You should not use rubber valve stems or valve extenders with the Corssfire system. The braided steel hoses are heavy duty and have some weight to them. With the centrifugal force when spinning, it will pull on the rubber valve stems. Over time they could tear and cause a leak.
2) Our recommended tire pressure front and back is 61 psi. The Crossfires I see are listed as 105 or 110 psi. Are they okay? Guessing the higher numbers are upper limits.
- Crossfire comes calibrated for tire pressures from 65 to 125 PSI.
You must by the right Crossfire monitoring valve for the tire pressure you intend to run. If you plan to run 61 PSI, you could geta away with the 65 PSI model because you will gain pressure once you are rolling and the tires heat up. However, you cannot buy a 105 PSI rated valve because when the tire pressure you are running is much lower than the rating because the valve id designed to shut off when it senses a tire is well below the target pressure to prevent both tires from losing air should a blow out or fast leal occur.
Also, the Crossfire is color coded. When the pressue is below the target pressure, the valve read yellow. When it is at the target pressure it reads black. When the pressure is above the target pressure is reads read. This is another reason you have to buy the correct Crossfire package that is rated for the pressure you intend to run.
Finally, Crossfire does sell an optional kit to be able to run an aftermarket TMPS with the system so you can still monitor pressures in the coach.
3) Also, not sure why the outer tires have valve stems pointed inward.
- Answered above. You just need a filler like this one that can read from either side.