I use Ansgars HPDRIVE software in a ThinClient without keyboard and screen.
I control HPDRIVE using a small box with an Arduino and a serial interface. In the thin client I use a small server program which links the serial interface with the remote control channel of HPDRIVE.
Your solution would be smaller and more convenient that using the ThinClient + Arduino.
But you would want a similar user interface like my solution.
To select the disk images my Arduino box has 3 moment switches and one of these cheap I2C 2-line LCD displays.
When starting the system I scan the disk for LIF image files and create a list. The first file name is then shown in the LCD display and with two of the buttons I can scroll up and down through the list. The name of the corresponding image file is shown on the screen. The third button confirms the selection. and tell HPDRIVE to use this image.
So: three buttons plus a one or two line LCD display would make a good user interface. These displays are cheap and are easy to obtain. With I2C it is only 4 wires - simpler than a hex display. It is very useful to read the disk image name (e.g. "HP85-Std-Pak") in the display.
[One "drawback" of HPDRIVE is that I cannot change the disk geometry on the fly. Once I set it up for e.g. 9122 disks I can only switch between such disk images, not between floppy and hard disk images. Thus it would be nice if the disk geometry could be changed too, e.g. based on file size or file name extension. This is not a severe restriction, just a tiny annoyance which could be overcome by restarting HPDRIVE]