Hi Martina
Sharon Shamber has 3 videos that might help. Maybe you already know them. Check her youtube channel and look for ‘stretching a block’ ‘shrinking a block’ and ‘magical basting’ which deals with squaring up a quilt. Sorry I can’t answer your specific question.
Lefty - in Philly

Sometimes you can sew outside one seam allowance reducing the extra amount. I do this by hand as I feel I have more control. I rarely undo as I hate this job and think it is toooooooo upsetting . I have undone to try to set seam narrower but not as successful.

I rarely ease a block to a block and if I had to I would probably not go more than 1/4 inch. I did a guild quilt and requested about 8 10 blocks more than I needed. Those blocks that were way off, I just pulled partially apart and redid them or "increased an internal seam or two. With Blocks that were too small - I found that the 1/4 inch seam was somewhat closer to 3/8 and when I was desperate would rework them completely.

Good luck - Oh ... one last option is "frame" each block with background material and square them all evenly - this way you do not loose points and do not have the rework anything!!

Thanks for all the feedback. The top at this point is already at 62" (-ish) and there is no way that I would dismantle it and resew from the center out. I will try to trim what I can to even things out, and then see what will stretch and what will ease as best as I can. The rest is up to the final owner. She is actually the one who started sewing inconsistent seam lines. And yes, I think I will bow out of group projects for a while. Too many other UFOs anyway.

When I have to ease fabrics I take hold of both layers making sure they match up an hols the fabric up at an angle form the needle. It works most of the rime.

Put the longest (baggy) fabric on the bottom and hold the seams you want to match between your fingers and hold a little tension on it so that it has to work to feed through the machine. This will give the feed dogs opportunity to grab the baggy fabric and work harder to get it to feed through the machine and it eases in the bottom fabric. If you are trying to match long strips, divide them into fourths or eighths, depending on how much you need to ease in and work only a section at a time in order to distribute the fullness evenly. If some fullness is on the top and some is on the bottom you may have to cut your thread and sew from the opposite side to make this work best. It may look a little "gathered" in some areas but usually works out when put over the batting. Use polyester batting with more loft for best results.

What iffy298 said! It definitely helps.

Sorry. Meant "ifty".

I have taken a block apart and re-did it. It was a shoebox club project and the block was awful...nothing lined up so I just re-did it.

How about 'taking in' some of the smaller seams a bit, to make it closer to square? I do this all the time-- take in or let out seams-- when my rows don't match up right.