I did pretty much exactly the same thing with a 3 gallon sized tupperdor and three 69% boveda packs. Per my hygrometer, it started at about 62% and after a month is up to 66%. I loaded it after a couple of days with about 150 cigars that had been sitting in wooden desktop humidors and were already properly conditioned (and I like my cigars on the dry side). So don't know if that would have slowed down the increase in rh. I think it was the dry cigar boxes and cedar sheets I used. So anyway, for me it's been a very gradual climb in RH. Btw, temp has been steady at 68-69 degrees.