The Challenge of Garter Stitch

One of the wonderful characteristics of garter stitch is that when knitted at the right tension (not too tight, not too loose), you get the same number of stitches as ridges (not rows!) per inch. This is what makes right-angled mitres possible. It's great, but it's also not great. In Harriet, it means that length and width grow proportionately. In other words, to achieve the desired width, you have to add on an equal amount of length. This is a number-crunching day, a day when I work out how to make the design work in a range of sizes.

I'd like to offer this pattern in as wide a range as possible, without sacrificing the shape and fit. Definitely challenging.
While this is going on, I'm previewing my button options. From my current selection:

I think the tree on the upper right is my fave, but I'm not sure if it will fit the buttonholes (this time, I built them in rather than adding them on at the end). I'll have to wait until it's dry to see. Thoughts?
It's so cold here today that I've hauled out leggings, wool socks, and my Perth Cardi. It's only 14C (about 57F), and we've given in and turned the furnace on for a while to take the chill off the place. That might also be why I'm in the mood to add to next winter's sock selections by knitting up a new pair of Urban Rustic Socks. (Just a little something to tide me over until I finish the calculations.)

Just love Ella rae Classic Heathers. The colour is 101, a sort of north Atlantic blue-grey. Suits the day. It just started to rain.