I'm not sure what you mean by batch priming. Unless you're mixing your beer with the priming sugar in the bottling bucket. Which is what I do now. I use the Northern Brewer priming sugar calculator and a scale. It seems to work fine.I’ve never had luck adding sugar directly to each bottle. First is the sanitation issue. Second is the math required and minute measurements. Anybody ever try to reload .25 caliber bullets?
Batch priming is where I’ve had the best success. You’re measuring a bigger quantity of sugar and boiling that in a small amount of water, which should solve any sanitation issues.
I’m bottling 30 at a time with mixed success depending on which priming calculator I use. And I do own a gram scale. It understandably has to be even harder at the 1 gallon level.