I've done the searches and found a little info that I have read, but need a little more please.

I have 2 Widdow Pl's. 1 at 58@28, 1 at 61@28,

Also have a PCH 65@28 coming shortly.

My question is..What spine do you think I need?, the 250 or the 300?

I'm looking at a finished arrow weight in the neighborhood of 750 grains or so.

Anyone?  :confused:

Either spine might be a little too stiff unless you shoot a long arrow or a really heavy foc.  I think easton made these arrows for really heavy draw weights.  Just my opinion though.

Both would be more than capable of filling the spot. the 300's would most likely come into the 600ish gr. range. The 250's would reach your goal, but you most likely will need a very heavy head up front(not sure of your preference on this), and it would also most likely require quite a bit of some some arrow hanging out the front to spine right. But as long as it's tuned they both can fly equally as well from your bows.
Personally, I would use a 300, and if it doesn't satisfy you in overall arrow mass wise, use weight tubes.

My thoughts anyhow.    
HaVE fun with it,
Ethan

http://www.eastonarchery.com/products/selection

Just a thought.

300

I shoot 300s out of my 62lb. PTF Widow with a 150gr. broadhead out front and 2 gr. per inch weight tubes inside. My arrows are 29.5 inches long and weigh in at 545gr. You can figure out from that what the other weight tubes would give you for total arrow weight. I would think if you plan on using a fairly heavy head for the new bow you have ordered you probably will need the 250s for it.

I forgot to mention I'm shooting Beman ICS Hunter shafts. The full metal jacket shafts probably weigh more per inch than my Bemans.

you will get your weight you desire and then some
the 250 spine is 17.2gpi and the 300's are 15.5gpi...the 250's I had well over 800 + grains with 250 point  remember these are totally different than the regular FMJ  weight wise that is

These are made for compounds, so you'll have to do something to weaken the spine. As mentioned, go long, or very heavy up front, but I bet you'll get there. Good shafts.

300s should work.  H

I shot 300's out of my 67# longbow, great flight but penetrated 2" less than my 340 FMJ which weighed over 100gr. less.

300's would be my choice, Rick.

300's.

Good luck!