Also I do not understand what you mean by a usb touch screen monitor as any video monitor
must get its main content from your computer's video output which would not normally be from
usb. Please explain what you mean.
I imagine he means a small (7 - 10") USB touch screen monitor. They do NOT use the video output - they have an inbuilt video chip which is driven over USB using custom drivers. Too slow for anything requiring heavy graphics but sort-of work although drivers can be fiddly and flakey. They cannot do anything until the drivers are loaded, so you can't boot with them meaning they are strictly a supplementary screen.Touch screen input is often rather imprecise and laggy - they tend to use cheap resistive sensing which works better with a stylus than a finger. Plenty of them about eg
https://www.amazon.co.uk/Lilliput-UM1010T-Monitor-USB-powered-Screen/dp/B003DPOMAS Haven't used them with Hauptwerk myself but I'm sure they would work with the limitations above - far from ideal but usable. An alternative to a cheap tablet with remote desktop software.