I have been planning to make a Wiksten Tank for over a year now, and I finally finished it up!
I made the dress version as a muslin a year ago with some stash fabric I already had--another cotton, but a lighter, floatier cotton than this fabric (by Rae Ritchie from the Desert Bloom Collection.) I found there was too much fabric in the upper back with that muslin, so on this version I took about an inch out of the upper back simply by angling the placement of the back when cutting it out, as described here. I cut a size S, based on my muslin and my old bust size of 33". TMI: Since then I've switched birth control methods and my breasts have grown a little, so I'm more like a 34" now. I discovered this fact when I found the bust area too snug once I tried my tank on! I wound up unpicking the top third of the French seams and redoing them with smaller seam allowances so I would have enough room in my bust area.
I decided to lengthen and widen the armholes based on my favorite Madewell tank top, since I found them too tight for my liking. I just laid that tank top over this one, traced the new armhole lines and trimmed the excess fabric off. It wasn't a lot, maybe 1/2-3/4" at most at the bottom of the armhole, but it did change the curve slightly in a way that better accommodates my arms/shoulders, or at least my fit preferences for that area! I had to add some extra fabric to the bias facings for the armholes to accommodate the new dimensions, so I fudged it by adding a little piece onto my existing bias strip rather than cut a whole new one because I'm lazy, and it's going in my goddamn armpit anyway, who cares! I followed this Grainline Studio tutorial for the arms and neck since I was having a hard time understanding the Wiksten directions.
However, I have some issues with the overall finished product that I THINK is due to my material choice, but I'd love to hear advice from more experienced sewists on it. This cotton was listed as being fine for quilting and apparel, though after reading up on the 'can quilting cottons be used for garments' debate that I was unaware of, I suspect that this cotton would be better suited for more structured garments and not a floaty tank top. It's funny--I'm so comfortable with yarn choice that I don't question myself in that area, but now I'm realizing how unfamiliar I am with fabrics and that I need to be extra careful in buying online!
You can see below how the tank fits decently (I think...) in the upper back, but the extra fabric in the body due to the A-line shape just pools weirdly due to the stiff cotton rather than flowing away from my body. That's the fabric's fault, right? Right?!
If you look back at the top photo, the bottom center of the neckline tends to flip out a little. Not sure what causes that!
Another mystery to me is the below issue. When I'm moving around and not adjusting the garment, tugging it down, etc, it creeps up and I get the armhole gap and raised shoulder/back neck as seen on the left. On the right is how it fits when I adjust it back down.
I have to admit, I really loved this print so I'm bummed this isn't the tank of my dreams, but I've convinced myself (rightly or wrongly!) that it's simply a bad fabric choice for this garment and not due to my newb sewing skills, so I've accepted the flaws. It looks fabulous with a cardigan on though! I'm looking forward to trying the Wiksten Tank again with a more drapey fabric, and would love to hear from you all about your tank fitting wisdom.