So than, how does one test for acetylcholine and how to balance this?
Testing of acetylcholine levels is not a standard test, so I don't know where this can be done off hand. Symptoms of low acetylcholine are one way of determining possible low levels. Symptoms can include age associated memory loss, muscle tremors and as pointed out anxiety. Low acetylcholine induced anxiety though would not induce the hyperventilation of lactate induced anxiety though, so there is a way of differentiating.
As for how to get acetylcholine levels up this is primarily through supplying the body with choline sources. Eggs, soy and sunflower seeds are examples of food sources. Lecithin granules are a rich source and there is also a supplement known as choline bitartrate.
Methylation is also needed for the production of acetylcholine. Here methyl donors such as trimethylglycine (TMG), dimethylglycine (DMG) or SAMe can be used or methyl donor precursors such as B6, B12 and folate. I prefer TMG for a number of reasons including very low cost, easy absorption and being more effective.
Choline itself is also a methyl donor and actually stronger than TMG, but it cannot be used in higher doses for cases such as undermethylaltors.