Multiple Arrow related questions

[Yazoo Bowhunter]

A few arrow questions for y'all TGs from a newbie:

A)There is a fellow TG-er near my house who's my mentor.  Our heights and weights are compatible (me: 6'4, 175lbs, him: 6'2, 200lbs) and our draw is almost exactly the same (mine is just a tad bit bigger).  In fact, I bought my bow from him.  Also we both shoot identical arrows - Carbon Express 250s).  So here's the question.

He uses 145grn field points and I've been using 100s and 125s.  For some reason it always just seems that when I shoot his arrows they fly more accurately from my bow than mine do.  In fact, I would certainly pick his arrows for critical shots over mine any day.  I don't understand why 50 grs really makes that much of a difference.  He mentioned something w/ the spine, but can someone else explain.  What's y'alls thoughts?  I went out and bought some 145gr points and will experiment today, but I'm just curious as to why 50grns could really make that much of a difference.  Doesn't seem like a whole lot of weight.

B)  I need to refletch my arrows.  I'm right handed.  I bought fletching. The guy at the store - Viking Archery in Houston TX - told me that my current fletchings are backwards for a right handed shooter.  Either they're right helical and need to be left or vice versa. I don't remember.  Can someone explain this to me as well.  What do I need?  Which way?  Does it raelly matter?

THANKS!

[aromakr]

Yazoo:
 A. When you add weight to the point it weakens the spine, indicating your's are a tad too stiff. Fifty grains is quite a bit on an arrow.

 B. The guy at the store is incorrect. It does not matter if you shoot right or left wing, just make sure all the feathers on the arrow are the same wing.

Bob

[Matt Green]

Anohter way to think of the wt is to compute it as grains per lb of draw - as pointed out, 50grains moves you from shooting an arrow say 9grains per lb to 10 grains per lb on a 50lb bow.

I agree - dominant hand doesn't matter.  Ferguson likes a certain wing b/c it doesn't hit his bow hand coming off the riser.  I prefer right wing b/c as the arrow enters the target, this spin direction tightens the field tips.
just my 2cents

[AllenR]

Arrow spine can be a very complex subject.  Some of the real tech nerds try to understand it based on vibration frequency and aerodynamics.  Joe Tapley has some of this math on his website.  Even though I have a pretty good technical background, I don't want to bother trying to understand his work.  I admire it, but I don't understand it.  

Fortunately there are easier ways to figure it out.  The standard seems to be the bare shaft tuning.  

What you are trying to do is to time the oscilation of the shaft so that it doesn't contact the riser at any point in the arrows flight.  The second thing is to achieve good arrow flight. That is you want the tail of the arrow to follow directly behind the point during flight.

Both of these can be achieved with bare shaft tuning.  You can go a bit further with fine tuning if you want, but that will get you started.

There are excellent instructions for bare shaft tuning on the A & H Archery website.  They are one of the TG sponsors.  You can also download the Easton Tuning Guide from their website.

Hope this helps,
Allen