Larger bottles - how much priming sugar?

I've noticed that the carbonation is excessive when using a large bottle, such as a growler, when bottling using the standard 3/4 cup sugar for priming. That would make sense since a keg only needs 1/3 cup - I think it's got something to do with the bigger the vessel of beer, the more activity of the yeast inside when priming sugar added. Any thoughts on this? I want to fill a couple of growlers as well as my standard Samuel Smith's bottles next time I bottle . Those Sammy Smith's are the best, IMHO - they're clear (you can see the color and clarity of the brew) (yeah I know, light struck is a problem -so don't take em out in the sun, dummy!!!- I keep my brew in the man cave!), they're tough as nails, and ya need only 30 or so to bottle up a 5 gal batch.

The amount of priming sugar doesn't depend on the size of the container. Determine the number of volumes of CO2 you want for your beer, and based on the current temperature of your beer, add the correct amount of sugar to a couple cups of water, boil it for ten minutes or so, then cool before mixing it into you beer before bottling. There are calculators online that will calc the amount of sugar needed, otherwise brewing software can do this.

A couple other points:
* Growlers are not intended to be vessels for carbonating beer. They are relatively thin-walled and can't handle the pressure. They're intended as a means to temporarily store or transfer pre-carbonated (kegged) beer.
* If you use clear bottles (or green), keeping them completely out of the light is your best bet to avoid skunking. Just avoiding direct sunlight isn't enough protection, kept inside a box is better.
* Measure your priming sugar by weight, since measuring by volume is not accurate. 3/4 cup of table sugar isn't the same as 3/4 cup of table sugar. I use a digital scale which I also use for weighing hops and malt.

Yes, but still ... why is it that every recipe I've ever seen has the 2 amounts (3/4 cup for bottling 5 gal; 1/3 cup for kegging the same) ?

I recently asked the same question and never got a satisfactory answer. I'm in the same boat and have found when bottling half gallon or gallon containers that they are way overcarbonated.

Since I prime the entire 5 gallon batch in a bottling bucket, the concentration of priming sugar is the same whether I put it in a gallon container or a 12 oz. bottle. The other day, while bottling, I had an epiphany. Maybe it doesn't have anything to do with the priming sugar, but rather the amount of air space at the top of the bottle.

For example, when using my bottle filler on 12 oz bottles, I get the perfect amount of air gap at the top of the bottle that equates to maybe 1 oz of volume. Therefore the ratio of air gap to beer is 1:12. However, when filling a gallon container, I leave the same amount of air gap. Therefore my ratio of air gap to beer is 1:128. It may be that the over carbing is happening because there is not enough air space to compress and use up some of the CO2.

So, if you bottle various sizes, should you change the amount of priming sugar or adjust the amount of air gap you leave at the top of the bottle? I've gotta believe there is a chart for this somewhere, but I haven't been able to find one yet.