Arrow tuning quetions.

[Prarie Bowyer]

Ok so I have like 20 arrows.  Mostly all cane and mostly different spine weights.  I tried scraping some down to reduce them and it's pretty slow going.  I'm thinking it's easier to  make new ones for my new bow.  Several are the same weight BUT it's stiffer because my last bow was higher poundage.

I'm curious about something.  I know that too stiff a shaft will send shots left of target and can cause porpising.  What if the weight is a little too light?

I have one arrow with a stone tip that works great from my new bow.  I have no Idea what it's spine weight is or the head weigth but I'm thinking of making more just like it.  I have a digital kitchen scale.  Is there a way to convert grams to grains?

I've been watching that Otzi Arrow Buildalong video and thinking of making removable foreshaft arrows with cane bodies.

If I got the new arrow set route what are some rules of thumb for optimizing arrow spine weight, actual grain weight and head weight?    Should the inserts for Otzi Type be an extra extension from the normal size arrow I use or they shorten the shaft to splice in the head?

[M-P]

Howdy,   One gram = 15.5 grains ( or close to that anyway.)   Grain to gram conversion charts are available online.   
You'll get the best results using a matched set of arrows.   Three rivers has a nifty little chart to help you select a shaft spine based on draw length, draw weight and point weight and center shot vs. a long bow.   
There are a bunch of other variables if you shoot an extra wide handled bow or perhaps leave the shaft significantly longer than the actual draw length.   A fitted foreshaft makes the arrow fall into that last category.   I believe that it is usual to only draw to the binding at the base of the foreshaft.  Cane, bamboo and tapered shafting all are reputed to make spine selection a little less critical.   Over-long or foreshafted arrows also are reputed to make spine less critical.
My suggestions   1)   Take a look at the 3Rivers chart for a first approximation of spine. 
2)  Go slightly less stiff if you have a realy wide-handled bow.  Go slightly stiffer if you are going to use a foreshaft, long arrow or extra-heavy point.
3) Make a couple of arrows and see how they fly.   If you have one that hits where you think it should, then make the rest to match that good arrow!
Ron

[Fred Arnold]

I'm not a cane arrow fan although I have tried them, they don't stack up in my opinion to bamboo and wood shafts that I've used.

"Generally speaking" it seems to me that when working with bamboo, weight and diameter are, as if not more important, than actual spine readings.  Bamboo is a very forgiving shaft material and I've found that well matched in weight and length can be off as much as 10# in spine and not create a substantial problem.

You may have to tweak FOC with minor front end weight which is very easy to accomplish.

Now I have to go back and reread your post to see if I'm capable of giving my opinion on one of your other questions. And that's all this was JMO.

[Prarie Bowyer]

How would you tweak front end weight after a stone head is put on?

[M-P]

Just thinking, but  if you were using a foreshaft, you'd remove the foreshaft/ head and replace with a heavier/ lighter foreshaft/ head.   Or if using a single piece shaft, you'd just have to change to a lighter. or heavier head.    If you're using cane or bamboo you have the option of drilling out the head end of the shaft and inserting a piece of metal to increase weight.   Ron

How would you tweak front end weight after a stone head is put on?