Picking up stitches/gauge changes

I got a wool sweater at a yard sale and took it apart to make soakers out of. I found live stitches when I did this, so I started frogging the sleeves. I sewed the two sleeves together at the seam (to form a crotch), and frogged down to that point. I picked up the stitches on size 4s (about 120 stitches). This is a 7 ply yarn (some places it’s 5 ply?). Can I knit off the 4s onto an 8 (I only have an 8 and an 11 in circular)? I know that’s going to change the gauge considerably… is there a way to deal with that? Or do I need to go buy a 4 or 5 circular?

You can reduce the number of stitches, maybe by as much as half when you switch to the 8’s. This way it won’t be huge. It will be looser fabric, though.