You are doing great. We had seen hummelincki ink for no reason at all (to us) even after they have been highly socialized (as in coming to our hands for petting). Quick movements will sometimes set this off and almost always if the are sleeping on the tank wall and you startle them awake.
Water changes are always recommended but as skywindsurfer points out, the larger tank will dilute it much faster.
In stead of not putting your hand in the tank to prevent inking, I would recommend doing it as often (albeit slowly and don't approach, let her approach you) as you can between now and the move. When it is time to move her you will likely have to guide her into the container and this is easier if she is not afraid of your hand. I have a great fish mover that I have used for two octopus tank moves. I videoed OhToo's move but did not get Monty's filmed. Monty was in a 15 gallon with a lot of LR so just getting it into the tank was difficult and required rock moving but the shape of the thing and the air hole at the top really makes herding them into it and moving them rather painless (not what we expected). You will need to place your hand over the opening once the octo is inside and it is not a long term holder but is great for transfers. As an aside, it does NOT work for pesky quick fish like chromis or damsels
Linda used a cut out milk jug with excellent results but el Diablo and her original tank were much larger.
Water changes are always recommended but as skywindsurfer points out, the larger tank will dilute it much faster.
In stead of not putting your hand in the tank to prevent inking, I would recommend doing it as often (albeit slowly and don't approach, let her approach you) as you can between now and the move. When it is time to move her you will likely have to guide her into the container and this is easier if she is not afraid of your hand. I have a great fish mover that I have used for two octopus tank moves. I videoed OhToo's move but did not get Monty's filmed. Monty was in a 15 gallon with a lot of LR so just getting it into the tank was difficult and required rock moving but the shape of the thing and the air hole at the top really makes herding them into it and moving them rather painless (not what we expected). You will need to place your hand over the opening once the octo is inside and it is not a long term holder but is great for transfers. As an aside, it does NOT work for pesky quick fish like chromis or damsels
Linda used a cut out milk jug with excellent results but el Diablo and her original tank were much larger.
GGRRREEEEAAATTT!!!! 
Now that Sedona is gone it just reminds me that Isis wont be around forever. And like D said in another post not having one is a whole lot sadder than having one for a short time. I would love to order one of these little guys.
