Not only does this sound like a great tip, it sounds like something I can do by myself!
Princess seams are awesome if you’re very busty and can give you a perfectly fitting blouse. When I was struggling to master adjustments for a full bust I cheated and wrapped myself (in my favourite bra) in cling/plastic wrap and then drew some lines where I though my side seam should sit (great if you have a side seam sew into a well fitted bra – use it as a guide) and a line from mid shoulder down across my nipple and vertically down to my waist.
Cut along the lines and you’ll end up with a perfect curve for the side bodice piece (that follows the contours of your bust) that you can transfer to your pattern.
Cheat method of doing a custom FBA for first timers *wink*