Let’s start with the most important thing first: most beginning sweater knitters select knitting patterns like they’re ordering something from a mail-order catalog. You look up your actual measurements in the chart, pick the closest size, and order, right? This works because the retailer has already taken something close to your measurements and added ease. Knitting Daily defines ease as “the extra fabric that allows space between you and your garments--space for things like moving, breathing, comfort, and extra layers of other clothing.”
Makes total sense. Except this isn’t the way it works in knitting. When you look at a size chart in knitting, you’re looking at the finished sizes, not the bust sizes (or whatever body part). So your first task in determining sweater size is deciding out how much ease you want by taking your basic measurements and adding ease for the bust, waist, and hips (and sometimes other body parts like upper arms if they are wide).
So, assuming you have a 46-inch bust and want a standard fitting sweater, you usually add four inches. If you want a snugger sweater, you’d add zero or two inches of ease. If you want baggy, you’d add six or eight. But the Slip Stitch Pullover looks like it needs pretty standard ease, so let's assume four inches. This necessitates a 50-inch finished bust size.
(Caveat knitter: larger people need additional ease - I think. I’m still working this out for sure, but I know from experience that garments knit with four inches of ease are snug on me. So if you’ve got a 58-inch bust like I do, you should probably add five or six inches of ease rather than four.)
Given my personal experience, I’d bet that the latter would be the most flattering. I’ve found that I look best in clothes that actually fit. When I buy apparel to accommodate my mighty derriere, it's much too large through the bodice. The best thing for me is to make the bodice fit perfectly and then to accommodate the hips, rather than the other way around.
Next steps: she needs to determine whether she wants an A-line or a modified A-line. If she decides on the latter, she needs to determine the length between her waist and hips so she can figure out the decreases. Which reminds me of another Fit to Flatter rule: for bottom-heavy women, have the sweater end above your largest part. When you make the sweater too long, it wraps around your hips and emphasizes them. For example, the pink sweater below looks better than the green one on my hips anyway - and I'm 50 pounds thinner in the green sweater. They're both too long though. I'm making my new Spencer sweater shorter - we'll see how it looks when I'm done.
One final warning: If our intrepid knitter wants to make sweater, she MUST make an highly accurate gauge swatch. She MUST meet gauge. Being a quarter stitch off gauge doesn't sound like much, but over the course of 59 inches, she'd add more about 2.5 inches to the width of her garment. You've heard it before and you'll hear it again: if you do not meet pattern gauge, the sweater will not fit. No way, no how. Yes, I know. Swatches are boring. But if you’re going to make sweaters, you have to meet gauge. Period.
After our intrepid knitter gets gauge and makes a fundamental decision about garment shape, it will be time to figure out decreases. Stay tuned.
In the meantime, here's a quick update about my Spencer sweater. As you can see, I'm unknitting the original stockinette version and reknitting it as the new lace rendition.