My 1st Grow! Gelato from own seed bank

Plants tolerated 1/2 strength nutes well last week, so I mixed up nutes for this week at ¾ strength. When I went to feed, noticed roots starting to poke out of sides of bag, so I need to transplant them to their final pot (3 gal fabric). Gelato is susceptible to transplant shock, so I didn't want to transplant and increase nutes on the same day. If plants tolerate this feed well, will transplant on next feed day. (Just saw a grow diary by Tripaholic88 who transplanted Gelato twice in 2 weeks with no problem, so I'm probably being paranoid...but I'm OK with that on my first grow) Also noticed what could be the start of some heat/light stress, so I raised the light a few inches to compensate for plant growth and get back to approx 24" from top of plants. Am struggling to keep the humidity up...waiting on humidifier ordered a week ago. By end of week, thought I noticed the beginning of some tip burn, so I'm going back to nutrients at ½ strength and changing the lights to an 18/6 schedule.