Bevin Tank - Major Set-Back

I had hoped to finish Bevin Tank today. It was possible, if the knit hasn't turned out to be a major disappointment. I wanted a modest neckline. And I know the pattern is a medium/large size. So I modified the pattern to shorten the shoulder straps and BOed the center stitches for the neck opening at 95th row (instead of 91st per pattern.) I BOed my shoulder straps at 133rd row, instead of 149th row per pattern. It is still unwearable.

The thing is, this yarn is super stretchy. The shoulder straps measured 6.5" long when the garment is laid flat, which is the exact length I want. But, when I tried it on, the straps stretched and draped, dragged down by the weight of the garment, to 8". The armholes are also too big, half of my bra straps was showing (that's why you won't see pictures of me modeling the top.) I keep wondering, if anyone else has finished this top exactly per pattern, and what it looks like on a real body? Maybe the pattern works better on people with fuller figures...

I definitely need to rip part of it out. I am not sure if I should rip it back to the beginning of armhole shaping, or just re-do the neck and shoulder strap portion? Oh, I hate ripping...