There's a dirty little secret you should know...
Even if you had absolutely perfect polar alignment, and absolutely perfect balance, and absolutely perfect drive motors driving absolutely perfect axes moving at absolutely perfect sidereal rate...you still wouldn't be able to go more than 8-10 minutes unguided without trailing.
'Cause the stars don't move at sidereal rate everywhere in the sky. Or, at least, they don't *appear* to, and that's what matters (yes, actually the earth is moving and the stars are still...but the rate they appear to move because of the earth moving varies by latitude, local conditions, seeing, altitude of the stars above the horizon, upper atmosphere currents, and more...).
I don't mean to rain on anyone's party. But without software that's taking all of those things into account, and adjusting the mount rate in real-time, very long unguided exposures are out. Sometimes you still can't do them ever WITH that kind of software (though sometimes you can).