I have a similar setup on the bow but different spine arrows. I couldn't get the arrow to fly very well off the shelf. Seemed to lose some speed, too. I went to a cheap, plastic Hoyt rest and that seems to work fairly well for me. Drawn to 26.5", I get good flight from GT Traditional 400s, cut to 29", 200 gr heads & 50 gr inserts. Oddly, feather orientation wasn't an issue with 175 gr broadheads, even though the flight was a bit off. With 200 gr broadheads, suddenly the feather orientation mattered a ton. Go figure.
I'm playing around with some full-length 340s with the same heads/inserts and drawn to about 27". They bareshaft a bit stiff but they're impacting the same out to 20 yards and a few inches left at 25 yards. Fletched are grouping well.