In the past I have always saved a little bit of my wort for bottling. My last batch where I did that was an IPA with a gravity of ~1.060. It ended up being plenty carbonated after a week in 22 oz bottles and more carbonated than I wanted it to if I let it go any longer than that. I've decided to go with corn sugar or cane sugar at this point and did a calculation that said I should use about 10g to 20g per gallon for an IPA to get between 1.5-2.3 volume of CO2 (no wonder my IPA was over carbonated). I split my last batch into a couple of 1.5 L glass bottles for secondary fermentation to do an experiment with dry hopping, so I am looking to get 5 12 oz bottles out of each of those.
My question is how much of a difference will there be if I make a wort with the sugar vs just adding 1g-2g of straight sugar in each bottle. If I go with the straight sugar, I can do 5 iterations of say 1g, 1.25g, 1.5g, 1.75g, and 2g for the 5 beers so I can really figure out what level gives the proper carbonation. Otherwise I'm forced to pick a concentration and make a wort from the sugar.