The circles I cut have about a 4" diameter. To cut them, I've been using this jiffy rotary cutter Olfa makes that cuts circles. It saves a LOT of time and energy in cutting, but you do have to mark the centers and edges of the circles (I use a cardboard circle to do this) before you cut.
In a yard of quilting fabric, you usually can get between 100-110 circles. I buy several yards at a time and chain the finished yoyos as I go in rows of 5-10 which saves time in the final assembly and still allows for randomness in your overall design.
Starting with circles this size, it will take about 1500 to make a twin sized coverlet (50 rows of 30). I'm not sure if this covers an entire twin bed (I'd have to measure), but I typically use my quilts as decoration folded in half at the ends of beds anyhow or as something to curl up with.
It's a big project to undertake, but the rewards are pretty big too. Go for it! I'd love to see someone else's work besides my own.
