You are going to need lots of modulated reverb, delay, and a volume pedal. Since he is using two Strymon pedals you might have a extremely hard time getting that.
i'd suggest experimenting with fx-1 and fx-2 using slow gear and/or sound hold effects

take a look at patch in 49-3 if you have the factory ones the combination of slow gear, reverb and delay there should give you a fair starting point to get a bit close to this
but be sure to turn off the preamp and compressor; maybe change fx-2 to sound hold if you can pedal assign that to sustain a toggleable root note in the bg too
Youll need-
maybe delay
Maybe a detune as well

My RP500 has a very similar sounding factory preset, its basically gone overboard with above affects. Should be possible, the GT is very flexible with effects.