I've seen too many videos of Solo crashing into buildings because of doing an Orbit with the Solo app, then loosing the WiFi signal. RTH kicks in and Solo slams into the building trying to take a direct route back home.
If there's any chance you'll loose WiFi signal, and you can't set RTH high enough to clear any potential obstacles, don't use the Orbit Smart Shot in the Solo App. This is actually a "Guided" mode, not a "Mission". As stated above, use Tower, plan a "Mission" (you can use the Circle waypoint (same as Orbit) in a mission), and change the following parameters:
FS_GCS_ENABLE to = 2 (Enabled, but continue with Mission when in Auto Mode)
FS_THR_ENABLE to = 2 (Enabled, but continue with Mission when in Auto Mode)
"If" you do loose WiFi during your mission, Solo will just continue with your planned mission without RTH. Once the obstruction (building) is cleared, you'll have full signal and control again. Also as mentioned above, be sure to let Tower append your mission with the RTH at the end (just to be safe it comes home when the mission is completed). You can still pres FLY to land yourself, once Solo is back in WiFi range.