I used the origami fold coverless. I just tied the corners. To increase the height, you can fold it so the triangle is lower on back, basically there is only one layer at the top in the back. My babies wore all their britches low rise, so it would have been tied around their hips. If you want better protection around the thighs you can roll the edges in jelly-roll style before you tie it. I never cared about that unless I was trying to get a cover over it, tho (my kids were ECed, so I didn't worry about blow outs, no advice there).
This is my youngest at 10 months in a tied origami fold (flannel sheet, unsure of the dimensions).

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