The number of stars in the G17 is about the same as in the UCAC4. The G17 and G16 are based on the very latest and accurate Gaia catalogue and have the advantage they allow 180 degrees field-of-view but also small fields. The stars have however no number/destination except for an artificial based on the ra&dec position.
The UCAC4 allows only small field-of-view but has three minor advantages
1) The stars have a label. (hardly any advantage)
2) Star proper motion is included.
3) Most stars have some color data. See status bar.
The most important advantage is proper motion. If you want to simulate star movement over decennia or centuries, you can do that in simulation mode with the UCAC4.
I would just keep it you have space but use primary the G17 for imaging and the G16 for visual work
Place the UCAC4 somewhere on you home folder and link HNSKY to it.