Connecting neutrals in disconnect switch
For the 240V single-phase 60A circuit to my shop I used a 3-phase disconnect. It had 3 switched terminals, and also a ground lug bonded to the case itself. The inspector was fine with this approach. 

Elsewhere for another project I used Polaris lugs which I got off eBay for a reasonable price, and were very easy to work with. Far simpler than using a split bolt and gobs of electrical tape and other supplies. But that said, a split bolt would work perfectly well if installed correctly.