I'll weigh in again on the inches / yds thing. I'd like to reiterate however that what works for YOU is the right way. Now...
The difference between multiplying by a constant (27.78) or dividing by a constant (36) is exactly that... either you use the x on the calc or you use the /. Arguing about which is better is silly. The real issue that folks get all worked up over is the little dot (decimal). When you multiply inches by 27.78 you get yards multiplied by 1000. If you multiplied inches by 0.02778 you'd get yards. By 2.778, yards times 100. Divide by 0.036, or 36, or 0.36, or even 36,000, go ahead, try it. You get the same answer, the difference is the order of magnitude. And if you can't or wont see that the target is 345 yds away instead of the 34.5 or 3450 yds that your calculator says, you've got bigger problems. Multiplying or dividing by any number that begins with 1 and is either followed or preceded by one or more 0's only moves the decimal, 2nd grade math. You all can argue forever about the operations and constants you choose to use (ie works for YOU) but the math is all the same.
One more opinion from me on this topic, then I'll get off my soapbox. The Mil-dot master is a fine tool, but it doesn't provide the precision needed if your target is small or the subtension is not a multiple of 0.25 or smaller than 1.0. There have been a few folks (not just me) that counsel precise measurement, to the 0.05 mil if possible, and the MDM just doesn't easily allow for it. I have one, I've used it, but I find that I'm more accurate and precise if I use a calculator and the method I outlined in post #14. As always YMMV.
-------------
Edit; Yea, it's generally easier to get a precise subtension on higher powers. But clarity of image becomes an issue sometimes too. (mirage) So use the power that allows the clearest and then biggest view of the thing you're measuring. I have backed off power just so I could see the edges without so much mirage.
Height, width, length, distance between... Any dimension as long as it's perpendicular to the line of sight.