I've written a very small program to make adjustments to a vMix countdown time. The main function is to adjust a clock to an exact time, ex/ 23:48. I've been using it with a num pad from a second machine (not required) on the network, which gives very quick and fine control of the time as I can keep the program in focus. With an xkeys I believe you could direct input directly to this without keeping focus; I'm not 100% on that one though.

Download for windows and mac from here - One Drive Folder

Github is here - https://github.com/dlamon1/vMixClocker

Enter your time with a period separating hour/minute/second; as follows:

12 - will give you 00:00:12

23.34 - will give you 00:23:34

17.34.23 - will give you 17:34:23