I really don't worry about exactness. I have gone through alot of steps to make a perfect quilt.After my 145th quilt they still aren't perfect. I just accept how they turn out.
I am very picky about everything I do and will redo things three times. If I can get it perfect after that I just move on.
Best way is to cut a bit larger and trim down, looks neater too.
I don't loose my points.
I have my way that works for me.
I never do block swaps, don't want someone else making blocks for me either.