there really are no quilt police, and you can use anything you want...if you like it use it, it's your quilt...if you make a practice block and decide you don't like it, then at least you've given it a try...if you make a practice block and love it...well, there you go...
i love working with homespuns, flannels, solids, prints...there is so much variety and a solid does not mean boring...if you don't believe me look at some Amish quilts...they are very bold and dramatic with great sparkle...and made with solids, not prints.
make the quilt your quilt and enjoy the process...
but when in doubt...make a practice block and see.