I haven't bothered with a second scale that measures really small quantities; I feel the age/quality of your yeast probably has a bigger effect on the dough than a 7/100-gram difference...
True enough. However, whilst yeast age and activity, and of course desired dough temperature and proofing environment all have a bearing on the finished product - I don't see any need to add to our already burdensome variables by mis-measuring the yeast.
In home recipe quantities - instant yeast (not as variable a product as fresh yeast or even active dried yeast) is often calculated at weights of around 0.3g - especially for poolishes and other preferments. Using a 1g scale, there's just no way you're even getting close to the requisite precision. One may as well be using volumetric measurements (eeeew). Example - a ciabatta recipe I made today called for 1/8th of a teaspoon of instant yeast. I was making a half batch, so 1/16th of a teaspoon. Fortunately, this is a simple measurement using a precision scale (and converting from tsp to weight: http://convert-to.com/537/instant-dry-yeast-converter-and-nutrition-information.html
) of 0.18g. In such scenarios, a "tiny" 0.2g difference would represent 100% too much yeast, or, to put it another way, you've just doubled the yeast that the formula called for.
A cheap set of jeweler's digital scales, capable of measuring 2-300g at 0.1 or 0.01g precision, is dirt cheap & are readily available.