I've got a collection of greenlee punchs that work way better than hole saws for sheet metal. Will check sizes later.
Like this, just need to drill a pilot hole, requires access to both sides though.
Does it have a split pulley where the V-gap changes for the different speeds? I think on these one part spins freely.
The last one I looked at like this had a shagged pulley. Cost $350 for a new one (not a husqy though, maybe they use a different system)