Newb trying to figure out what's wrong, help greatly appreciated.

Okay first off let me give you some background on this trooper of a plant. This was originally an outdoor plant a friend of mine gave to me after he found it growing on it's own outside. When he transplanted it a good 4/5ths of the root ball was sacrificed in the process and the upper growth was shriveled and dead so I had to clip the main stem a good ways down. So she's been through quite a bit of shock.

She has since been transplanted indoors to FFOF soil and only watered with distilled water so far (there have been NO NUTES added at all yet) and I haven't been watering until the soil has been dry a good 1/2 - 1 inch because I knew the root ball was in such horrid condition and didn't want to overwater her. It's been almost 3 weeks now and it has really taken off lately, however I am getting some canoeing (or cupping) at the edges of the top leaves mainly and some curling or clawing under of those same leaves. (see pics below)

So from all my research so far I think it could either be heat stress or humidity being too low. The heat is on average 79-82 with lights on (6 26W CFL) and about 73-75 with lights off. I know these temps are not ideal but it's an uphill battle with heat where I am and I didn't think those temps were THAT bad. The humidity is on average about 35%. I just wanted to check with more experienced growers if my diagnosis looks correct and if so, will this have a massively negative effect on the plant? I was thinking of getting a humidifier to help with the humidity issue but the heat is about as low as I can get it and I was really trying to avoid moving the lights away further due to the poor penetration of CFLs. But if it's going to hurt her that much then that's what needs to be done. Another possibility I was thinking was pH problems since the distilled (not spring or mineral) water actually tested out closer to 8.0 on my pH meter which had just been calibrated, but since there’s no nutes aside from whatever is in the FFOF I didn’t think that was a very likely reason.

Everything else with her seems fine she's been shooting out new growth pretty decently in the past week but I'm just worried I may be at the start of something catastrophic and want to avoid it if possible. Sorry for the essay and the not so great quality pictures. I really appreciate any help you guys can provide and please let me know if you need any additional info.

You might be on to something with your diagnosis on humidity as it looks like quite the sativa. All I can say is that's pretty similar to how my plants have looked when the temperature was too high.

Yeah I'm definitely going to give the humidifier a shot. Thanks for the response Doomah. Anyone else have any ideas or diagnosis?

You may be overwatering if those numbers are correct. You should always water your plants by the weight of the pot, not by the finger dip. Feel your pot when it's dry, and feel it after a full watering, and learn the difference. Water when you're pot is almost as light as when it was completely dry. 1/2 to 1 inch from the top isn't dry enough, if you're gonna use the finger method, it should at least be dry 3 to 4 inches down in a pot that size, but I always checked further down, as far as I could get. I don't use that method anymore though.

I was thinking maybe overwatering as well but I thought the dip method was a good way to tell, I'll definitely start learning my pots wet/dry weight now, thanks for the heads up on that. Overwatering would make sense too with how bad the rootball was damaged at the start, I'm sure it hasn't fully recovered yet. I'm gonna let her sit a few days more before watering next and see if that helps. Will the affected growth go back to normal as the water is used up? Just trying to see if there will be a visible indicator to tell me if that was the problem and if the waiting corrected it.

Yes if it's overwatering, the plants will definitely perk up as the soil dries out

Some of that looks like strain. I don't see canoeing really. I see some droop and thin, heavily textured leaves. Just looks too wet. Keep it going!

Is the heavily textured leaves indicative of anything or most likely just strain? I've just noticed some plants having more of a waxy texture to their leaves. Just playing wait and see right now I guess, anyone else care to weigh in?