I have just enough experience to be dangerous. And I love being unconventional.
Seriously, I'd like to hear your idea. If it was just a small amount, I was thinking I'd ease a little fullness where a regular dart would go since I'm using a knit fabric. But I need to FBA for a D/DD cup, so it's more than I think could be handled by ease (alone).
Christine, I am a DD person too. I do not always like the traditional FBA because at our size it curves that armhole just a little too much.
Although in the latest issue of Sewing Today the Palmer/Pletsch ladies have changed the FBA for large chest woman. It's worth looking at, although I saw something similar to this in another book. I can't remember the name, but it was written a few years ago by a couple of womem who worked at G Street Fabrics.
Anyway, my unconventional way of doing this will work because there are gathers in the front. It will be hit or miss because how much gathering in the front makes a difference in how this style looks in large chesties like us, IMO. So experimenting is the key. What is most important is get the proper length in the front. If you get the correct length in the front you will get rid of those pesky drag lines in the front. I know conventional wisdom says more width is needed to get rid of them, but I respectfully disagree. I strongly feel that is horizontal balance issue going on and not width.
I know for me that my front length to my waist is 3.25" longer than my back length to my waist. So I alter for that first,. I slice horizontally all the way across at the bust point and spread the amount needed.
BTW, this does mean that you have measured this on the pattern or at least found it printed somewhere. You need to know what difference in length has been drafted in before you can add what is needed. For example, I need 3.25" and 2" has been drafted in. (On my last top only 1/2" had been drafted in. Who did that make that for???!!!
) I would then add 1.25" in length to get my difference.
On top of this - I told you it was unconventional - You need to make sure that your back length is drafted correctily for you also. My full back length is 18". So I usually have to add an inch to the back at the waist and an inch to the front at the waist before I can even tackle the bust line.
Now that you have added the length in the front you can do one of two things. You can now draw in a horizontal dart pointing to the bust point, or you can take that extra length at the front side seam and move it to the neckline. You do this by drawing dart with the outer legs touching the top and bottom of the space you inserted and drawing to touch your bust point. Cut that wedge out. Then make one to two slashes at the neckline. I like to space them evenly apart, so I measure where the gathers go, divide by three and make two slash lines. Draw and slash these line to the bustpoint. Try not to cut through the bustpoint, but leave a little paper hinge. Now close up the horizontal dart and let the two slash lines spread open. The dart has now been transferred to the neckline. and as an added bonus you now have all the length you need in the front and you do not have have a curved front, which is actually some of the bust dart moved to the bottom. Study enough of those japanese sewing books and things start to click in the brain.
At this point you may also need more width, depending on how you start with a pattern in the first place. I start with a size 14 that has a 36 bust without ease and I am much larger than that number (I'll just say without saying the actual number). So I might need more width at this point, DEPENDING on how much width I have gained from the unconventional FBA, the style of the top, the fabric used, the look I want. In my personal experience, more width in this kinds of tops for a large chesty is not figure flattering. You want to wear it a closer fitting that what the pattern may be drafted at.
However, if you started with a pattern that was high bust measurement and only needed say 2-3" in extra width, that may already be built into whatever ease in drafted into the pattern. (I have no idea how much ease is built into this pattern as I don't own it. This is just my thought process as I approach a pattern) On my last top that didn't make the cut, the pattern had 11" of ease.
I only needed probaby 3-5" and I stupidly settled on 8" ease. I didn't need to do any FBA on that pattern at the 8" of ease using my HB. I could have gone down another 2 sizes probably.
So each pattern is different and how much ease makes a big difference on look and fit. There are alot of factors that go into each style. That is why I have started doing some alterations that are mainstream differently. Afterall it is what works for our body that is most important.
And like Denise says, you can leave the horizontal dart in if you want to. But I wouldn't recommend that unless you plan on 3" of ease or less. Otherwise it will float away from the body too much and not look right. And if you are making the sleeveless version, definitely do no more ease than 3" above your chest measurement. After that you start to reveal too much under the arms.
HTH and sorry to be so long winded.