Recently on an mid-September deer hunting backpack in eastern Nevada's Mt. Moriah area I was camped at 8,125' for two nights in my Tarptent Moment DW solo tent.
The second day there it rained for a full 7 hours of steady downpour. With rain that heavy I stayed in my little solo tent for, you guessed it, 7 hours! The rain stopped only to change to snow!
Anyway, by the next day the inside of my fly was full of condensation. I had to pack up the tent and get the inner tent soaked from the fly condensation. UGH! I vowed to try DWR on the inner tent.
When I got home I rinsed my tent in the bathtub as i always do after a trip. But this time I next soaked it in Granger's wash-in DWR solution. Then I hung it out to dry in the backyard. Since I live in the Las Vegas valley it dried quickly enough that by 3 PM I could spray it with REVIVEX DWR spray as a backup to the Grangers DWR.
Hopefully fly condensation will tend to roll off the inner tent. I'll be backpacking the Grand Canyon North Rim-to-South Rim in early November. I'll report back on the fly condensation situation & how the inner tent fared. If it works well I'll do my two person SCARP 2 inner tent the same way.