I'll be testing my portable HF setup on VarAC this week. I'm using an ICOM-705 and a Surface Go tablet. The antenna is an End Fed halfwave sloper with the apex at 25 feet. The combination works well on CW so it should do a nice job with VarAC.
I'll be active on both 20 and 40 meters beginning tonight (November 2) starting at 22:30z. See pics below.