My advise ... pick your pattern first! That will dictate what size your cuts into your precious scraps should be. I once cut mine in advance .. and the pattern I just feel in love with did not have the cooresponding dimensions of my ready cut scraps. Pick a flavor after you pick your pattern.. do you want modern, bright, earthy... that that be your guide in your scrap sorting. Then review the pattern one last time .. then cut.
I completely disagree with the concept of cutting scraps with no clue at hand of final pattern choice... My view is that it took me years to accumulate a good amount of scraps... and I find my scrap bin to have value .. just like my regular stash... I would not cut my regular stash without knowing what I was going to make.. so why would I do it with my scraps?!!