Help me with the maths!

[imsharris]

What size power bank would I need to power 1 Strymon pedal and a Yamaha MG06X for say a gig length of at least 2-3 hours? Small room volume with 1 acoustic guitar and 1 vocal. Acoustic guitar is a passive K&K running through a Red-Eye directly into the Yamaha. Strymon Flint is run through the Red-Eye effects loop. Microphone is a Sennheiser e935 run directly into the Yamaha. Vocals will use some reverb provided by the Yamaha. (It is possible that the Strymon will not be needed and the reverb for the guitar can be provided by the Yamaha as well. In this scenario, I would only need a power bank to power the MG06X. However, the MG06X does not have separate channel FX controls.)

Hopefully I asked the question correctly. Please let me know if any other information is needed!