What did the folks at Herd use for remote control?
Latency presents two problems:
1. When you reply to the other transmission, the other operator will wait for as long or longer of a half second for your reply.
2. After you finish your transmission, keep your transmitter keyed for at least an extra half second before you unkey.
It is a nuisance to do this but it, at least, gets you remoting.
Unfortunately what you are talking about may be "Science Project" in which you may need to test it to see if it works.
I also would.like to hear from the Heard Island team as o what they used.
No such luck for the rest of us. :(
I think I would gladly deal with the latency issue to gain the above two advantages. Might we arrange that you sign into our Smartlink enabled Flex stations and make the DX QSO for us?
You also might want to check that the contact will count against ARRL criteria if that is important to you. My vague understanding is that it would not unless your client station is in the same country as the remote station.