You have already had lots of great advice. I just can't help adding my two cents worth.....these vintage blocks are exquisite and a great historical story of fabric of that time. There is very real possibility it even has personal and family clothing in those blocks. I highly encourage you to be as authentic as possible when putting these into a quilt form. It would be a tragedy in my opinion to add rick rack or any other bright embellishment. But of course this is just my opinion. Again, they really are quite beautiful. Also you talked about not enough contrast. Google low volume quilts...they can be surprisingly beautiful.