How long should it take to get a decent rolling boil on the G70 / G70²?
It should take 40-60 minutes from sparging.
A tip is to switch the G70/ G70² to 99°C (210°F) while you are doing the sparge to speed up the time it takes to get to the boil.
By the time you finish the sparge, the G70 /G70² should be close to the temperature.
Note: This is automatically done when using a managed brew session in the app.