I hate my bedsheets.

Have grandma's ancient cast iron singer straight stitch sewing machine. Works great.

My new bedsheets suck. But I'm not returning them because I do like the material and color and the fact they were $19.93 on markdown for king size sheets.

I hate them because despite being labeled as for "deep mattresses" the top sheet is incredibly short and narrow. My old set I replaced because they were getting worn I could tuck a full 10" of the top sheet under the mattress and still had enough to wrap up and over and under my head.

If I leave enough to cover up to my neck there's only like 2" of sheet tucked under the mattress so it's constantly coming untucked.

I already solved the fitted sheet not being quite deep enough by sewing on some 3" elastic band across the corners.

I have an old sheet set still in great condition from my full size bed in the spare bedroom, and it's a complimentary blue to the new king set. I'm considering cutting off pieces to sew into the new top sheet to improve the length and drape.

What would you suggest I do for constructing the seam when I sew them? I've made a bunch of camping gear, like down jackets, and a hammock under quilt and top quilt. But all those sewn seams are generously hidden inside the baffles out of sight, out of mind.