I'll try and answer these in bulk.
First retaining the greens -- with the 665 conversion, at least on the GF1, the greens remain pretty "normal" which was a surprise and somewhat disappointing. However, it works for the fog shots.
On the two B&W's I tried to add a "halation" effect, and that is what causes the soft, hot look on the highlights.
Focus: Precision adjusted the focus for the IR band. However, with the GF1 conversion, the sensor gets set back a bit so you lose crisp infinity focus at the wide end -- 25 Meters seems about it at the 14 setting, but you get to maybe 100 meters at the 45 setting. There is apparently a lens fix for this but then the 14-45 loses a bit of close focus ability when used on a normal camera, so I am still considering that one.
So far, I not overly impressed with the contrast in the B&W conversions --- it seems about like a visible light conversion, albeit with a bit more contrast in the sky. I am also a bit dissatisfied that the greens remain so green, and don't go "light" -- this is a puzzle frankly. One thing I am going to experiment with is swapping the Green channel with the Blue instead of the Red and Blue in post. I am also going to try and get some more information from the folks at Precision -- who by the way are VERY easy to deal with and have been quite helpful and responsive to all my inquiries!
I didn't like the train shot either, simply because it doesn't even resemble IR -- and I posted it because of that.
The two tree and fog shots are my favorites too, and the lone tree is my stand out favorite, though I like the B&W barn shot too -- and FWIW that barn was bright red! But, the dark foreground on the barn is actually new green grass, while the lighter parts are patches of older dead grass...
Exposure: Exposures were pretty normal, all shots were hand-held, and most were like 1/30th to 1/60th at f5.6. One nice thing about the 665 conversion is you get usable exposures and can still add a 720nm filter for stronger IR effects when desired.