i spent a heckuva lotta time messing with carbons and made the whole process into a small science project to figure out what carbons are all about, how best to control them (instead of them controlling me) and doing it for the least amount of outlay and the largest gain in accuracy and performance.
SO, my opinion and recommendation is beman bowhunter carbon shafts, 500 size.
do not be overly concerned with spine, as a single carbon shaft spine can cover a very wide spectrum of stiffness and front end weights.
forget using any internal weight tubes, they're more bother than function in the long run. add all weight up front for both increased arrow weight and foc.
add the up front weight using a heavy brass insert, or heavy screw-in adapters (always use screw-in adapters and not screw-in points or broadheads - far more versatile for tuning).
make up ONE arrow, use any feather configuration ya like. you can precut the shaft tube to 29" or leave it at full length and cut it down in 1/4" increments at the nock end 'til the arrow flies well for ya. cut the carbon shafting with a dremel carbide wheel or fine razor saw - after cutting, lightly sand the tube end square using 120 or so emery board grit, push in the nock.
i use 29.5" beman 500 shafts almost exclusively with a 55# longbow @ my 29" draw. the shaft alone will weigh 235 grains. the supplied alum insert adds 20 grains for 255 grains. a 125gr adapter and 125 grain glue-in point (broadhead, field, judo - glue-in points are so much more versatile than screw-in points!) gives ya 250+ up front (for a good high 20% or more foc), and a total arrow weight of about 510 grains. that'd be about 9.5gpp for yer setup - not bad at all.
to up the arrow weight for a closer 10gpp (or lots more), increase the glue-in point weight or use heavier brass inserts (50-75-100gr) instead of the lightweight alums.