Everyone will have their own preferences and opinions with dry start, but for me, personally, I have the most success keeping it well sealed, only opening it maybe 2x a week. I didn't have a spray bottle at the time so i would just add water from my main tank with a yogurt cup or something until the water line was basically at or slightly below the substrate level from the lowest point in the substrate. I did this maybe once every 2 weeks, or as needed. (obviously within reason, though) IMHO, you want to crack the seal as infrequently as possible.
And one more thing i forgot to mention yesterday. You'll definitely want to split that hc up into little pieces. Individual stems are best. Giving it room to grow out will encourage a much stronger root structure, and it'll spread faster, which also helps to deter growth of mold, algae and etc. in the 5.5g in my signature, i planted one side in clumps and the other as stems. the stem side carpeted faster, looks better today, while the clump side contracted a virus halfway through and took much longer to reach the same coverage of the stem side, plus it ended up looking quite uneven for the longest time. These clumps were about 1/4 the size of yours, too.
You'll know it's humid enough when there's thick condensation on the glass and walls. When you crack the lid to check, it will feel noticeably sticky and humid to your bare hand. TO get to this point, you'll have to leave it for a few days to build up humidity without cracking the seal. There's pretty much nothing else you can do practically to raise humidity other than ths.
In the beginning, when your HC has been freshly brought out of submersed, it is a bit more delicate. However, when you start seeing fresh growth, I would actually up the wattage to 75 watts with desklamps and such. maybe just ditch the hood. the tank you have looks kind of high, so at the substrate level, the humidity should be somewhat higher than at the top.
Also. I here, with my coffee mug of instant ramen, envy your supper.