you might jig something up with a long threaded bolt and some sockets. The tool is specially contoured to sit against the pistons you are removing, but you are tossing them anyway. The tool is not expensive at all. I bought it to use it once and it was worth it. I recall around 20-30 bucks for it. the threads on mine are reversed, I almost broke it trying to get it apart to use it.
be VERY AFRAID of falling debris if you have the cageless bearings. certain death without full preparation will occur after the pin explosion that will follow unexpected pin shower from Rod to Piston bearing pins falling out of place.