I respect NightWing's post. I just received my first custom Blacktail bow from Norm Johnson 6 weeks ago. From talking to Norm, he's not much in favor of lighter weight arrows. From his literature he sent with the bow, his only recommendation is not to shoot less than 7 gpp with fast flight string.
To my knowledge, Norm's guarantee doesn't have a minimum grain per pound. But, if I was to build bows, I would have a minimum. On the other hand, I shoot bows, so my feelings on this side of the equasion are somewhat different.
That said, I've been going crazy trying to get arrows tuned to my new Blacktail. I've finally solved that today, 2 days before the season. I will be shooting ICS Bowhunter 500 with 150 gr Stinger 4 blades and 10 extra grains of brass washers. The bow is 48# at my 29 1/2". This will be 8.86 grains per pound.
I think this will be a great set up - not too light to cause trouble with Norm if there's trouble with the bow, not too heavy and all the problems that I don't want with heavy arrows.