Peaches, as for the acid test kit, I've only seen one kind myself - which I have, and sometimes use but its the least satisfying piece of "equipment" because I tend to make Reds, and you have to look for a color change in the sample while dripping drops of test-agent, and the color change is to a darker red. Hard to tell when the "change" is the change and when it's not quite a change, so I never really trust my readings -
You can get a PH Meter (pricier - the acid test kit is <$10 I think but a ph meter is >$30). A lot of people on this forum use 'the taste test' and that one is free. But, kind of means you have to know what the right amount of acid tastes like! (haven't seen that one fully defined either)
Bottom line is - haven't got any good advice on the acid test for you but if you dont have an acid test kit you can use "the taste test" - it the taste makes you pucker up and close your eyes, that's too much acid, and if it tastes like "huh?" that's probably not enough! LOL