Carbons are tougher. But you're going to pay a little more for the toughness.
Gold Tip blem's are pretty reasonable if you're starting out & are making your own.
As regards arrow size, it depends on your draw length & the weight of your bow at that length.
If as you wrote, you draw 27" & your bow is #51, somewhere around 29" would be close. Longer won't hurt. As you tune, you can shorten the arrow about 1/4 inch at a time until you get good flight. You want to leave at least an inch before the back of the point for knuckle clearance in front of the shelf when you're at full draw.
If Gold Tips, I'd start with 35/55 shafts & a 125 gr. field point. As you shorten them you're going to get closer to the #55 number which should bring you near what you're looking for. You can experiment with flight & tuning by going up or down in point weight.
Some will also recommend 55/75's & add weight up front until you achieve satisfactory flight.
It's all part of the fun!! Be patient & enjoy yourself!
Larry