"I wouldn't do it. Z-Poles are fragile enough as they are. Speaking from personal experience and of all my backpacking friends who were all on the Z-Pole wagon, I have not met someone who owned a pair that didn't prematurely break them. I'm sure there are plenty of exceptions, but from my own experience of watching how these poles fail in various situations, I would not trust them on a long distance trek, let alone with snow baskets."
Are you talking about the carbon fiber version? I have the aluminum version and find them more than adequately strong. I'm about 205lb and use them very aggressively. (Mind you, I have other issues with them, but not that.) So if someone knows a way to change the unchangeable tips (maybe so, see above), I wouldn't hesitate to give it a try, at least on the Al version.