For stability purposes, I picked up one of the bedside toilet frames at a thrift store. Ya know, the kind that an elderly parent might use when they spend much of their time bed bound and can't walk to the bathroom. I think the thrift store called it a handicapped bedside commode. Instead of using the small plastic bowl that comes with the seat & frame, I put a five gallon bucket underneath. I have a piece of plywood cut to fit over the top of the bucket because it is far easier to get off in a hurry than the normal bucket lid when I'm in urgent need to use the toilet. Very little urine goes into this bucket and a sawdust/soil (or fine
compost) mix is used for covering up. Once filled, the bucket lid snaps on, the lid gets dated (so that I know when it was filled and began aging), and it is stored away. I find that five gallon buckets are far, far easier for me to handle than something larger.