to HSI or not to HSI

Dave,

We could install a non-slaved NSD360 HSI instead for $3500.

Never realized that there is something like a _nonslaved_ HSI, but one never
stop learning ;-) Does that mean you have to handle it like a DG an
twist-the-knob regulary? I'm used to slaved HSI for a while now a found the
slaving one of the biggest improvements when moving up from a DG. Have you
considdered a slaved one? What's the additional cost (may be a lot, taking
into account the flux-gate, sync, installation, etc...)?

Best Regards

Kai