I had made the the front too small and there wasn't enough space for bust. The figure was all too flat when the stays were laced completely. So, I opened the lacing leaving a gap at the upper edge of the center front, as seen in the picture, to achieve the right shape. I was considering for a while whether I would just always wear them like this or if I should make new front pieces. Also, I was getting a bit frustrated because of so much tweaking on stays and felt like I should just go with the earlier pair of 1780's stays and give up with the new ones. But, in the end, realizing that the eyelets weren't positioned right either - the front pieces wouldn't meet evenly - I pulled myself together and decided to sew new front pieces. The pattern needed a little reconsidering. In the picture below, you can see a sketch of the original shape of the centre front piece. There were two options how I could give more space to the bust: you could curve out the line at the side or at the front. I chose the option I because I had lacing at the front and it could cause some problems if the centre front wasn't straight. I also needed a little more space at the armpit so the option I also allowed me to add space there at the same time.
So, I took the old front pieces away, sewed up the new front pieces and I got to try the stays on again yesterday. This time, it was a success.
I had made the tabs a little longer than in my earlier stays. It turned out to be a good idea, accompanied the curvy lines of the pattern, the tabs flare out very beautifully! Also, I gave the tabs more tooth-like shape like in many of the 1780's stays so I suppose they'll be also easier to bind.
Now the shape is finally what I was going for. The top edge curves up radically and supports the bust area from the sides and holds it in place preventing the breasts from flattening and sliding towards the sides.
I'm happy I had the patience to go on with these stays and not to give up with them. I've learned a lot during the process of fitting and pattern making of these stays and I really hope this post helps others who are pondering the same things I did. :) Hopefully next time as I'm posting I'll be able to show you pictures of the finished stays. We'll see about it later on!