I never use my precuts in set patterns, I buy them because I love making scrappy quilts and when I can get them at a deep discount. I don't think I'd own any if it weren't for MSQC's daily deals.

I don't buy layer cakes to use as squares. The size fits perfectly on most of my Go dies. Especially the BOB dies. Layer four squares on the die and get four perfectly cut pieces to make four Ohio Star blocks or any other of the BOB.

I would figure the cost difference between the yardage and layer cake then guesstimate how long it would take to cut all those 10" squares and see if the difference in price is worth it.

Yardage. Yardage. Yardage. You get more for your money and precuts are not always cut accurately.

Rhondals....please be advised that your math is incorrect if I'm correct in that you want 10 inch squares from yardage.
3 yards of fabric is 108 inches....divide that into 10 inch strips. You will get less than 11 strips (wof)....now divide those 10 inch strips into 10 inch blocks....only 4 from each strip!! You need more than 3 yards to get what you need...6 1/2 or 7 yards for miss cutting. If it were me, I'd just order the 10 inch squares from Missouri Star....3 packs of 40 per pack. You'll have left overs but can always so something with them.

Buy yardage. If you prewash (and with black you probably want to) yardage is easier. I used squares on a project and spray starch with no prewash. The starch made them shrink. I could see it happening...not a good feeling. Plus those squares are cut fairly good, but not always exactly perfect. So you have to decide which allows best use of your time and cash!
Have fun on your marathon trip. Sounds like fun!

Didn't someone here suggest that you buy 3 1/2 yds of black? That way, you'll have enough fabric. There's nothing worse than trying to find matching black. Good luck.

when usng dark colors like black, green or red either pre wash or color test as I have had problems with a lot of these colors bleeding that is why I prefer yardage and pre washing

I would cut my own from yardage. If I goofed some up then I could only blame myself. I would end up using them somewhere else.