Shed I'm glad your checking this out.
You're VPD is 0.3. Thats a bit too low. The plant wants you to keep moving the light closer until it's leaf temps are 2 degrees less than ambient. Your light isn't close enough to be "in the ballpark".
If you move it incrementally closer until the leaf is only 2 degrees different, your VPD would be 0.4, which is marginally low for that stage, but getting into the ballpark.
Then as you raise room temps and bring the humidity down, your VPD will climb, and you may have to start raising your light.
Grab a VPD calculator.
Here are a few different scenarios, but 1st lets assume you get the light hung where it gives a 2 degree difference, because thats what the plant wants, and that 2 degree difference is after the lights have been on for at least 9 hours.
Always try to find the max VPD value. Plants rev up as the day wears on.
If you set VPD in the morning, the plant will go higher than what you planned later on in the day, so if you are pushing them, use a later reading or you will over-rev them. I can't stress this part enough. It's important. Hermies suck.
So heres the scenarios.
Your current VPD.
What it would be if you moved your light in closer to get a 2 degree difference. Too low for that plant still.
Even higher with a 2% drop in RH. Almost where that plant should be for it's size.
A huge riise in room temp gives a small amount of extra VPD, That plant would love this
.
But this is way cheaper and even better
.
And this is where the plant is going.
There are lots of ways to make it work, and it works most efficiently at a 2 degree difference. The plant will raise or lower its leaf temp to adjust as the daily needs fluctuate, to vary VPD itself, but can only properly compensate if you are in the 2 degree ballpark. It doesn't like to shiver and it doesn't want a sunburn, it wants nice
. 2 degrees is nice
.
Also remember that light intensity, being 1/3 of VPD, directly effects stomata and stomata regulate CO2 intake, so if VPD is off, so is CO2 intake.
2 degrees, its an evaporation physics thing that optimizes rate of transpiration.
So if your lights run 12/12 from 6am to 6pm, take your VPD readings at 430 pm.
Don't worry about morning readings, they will be all over the place. The plant is switching gears from lights out respiration to lights on transpiration. It takes awhile to get things photosynthesizing properly.
It's the max reading that you should worry about. After an afternoon VPD check, make your adjustments and live with them for 24 hours until you check again.
Is the light still 10 inches away? What is leaf temp now? If it's still 10" away, check it again in 24 hours.
It usually takes about a week to first dial a plant in. The pendulum swings slowly on 24 hour adjustments. Once you get everything in the ballpark it gets easy to maintain.
I find that after getting the light adjusted, controlling RH is the most effective way to adjust your VPD. But if you live in a really humid area, adjusting heat may work better.
So Jon in Florida is hot and humid, Me in a Canadian desert is cool and dry. Check this out.
Jon in muggy Florida....
Me in the cool dry desert.
Our very different climates can be controlled 2 very different ways, to make the plant equally content.
Be careful, getting too close to the light to quickly will permanently damage leaves.
The higher the VPD, the faster you move water. The faster you move water, the muggier the tent gets. The muggier the tent the more airflow you need. Raising VPD without proper venting can invite both PM and bud rot.
You will know the moment you enter the ballpark, and the moment you exit it, your water consumption doesn't lie. If they start drinking less for no reason, your VPD likely dropped, if they are going dry really fast, your VPD likely spiked.
I don't open the tent without my IR gun in hand, but all readings are purely observational except 430pm. Thats the one I go by.
Gee! That was a lot of work to help someone with absolutely no environmental controls other than an oil heater in the room (otherwise it would be a daytime high of 64º in there!). 
and leaf temps in the, I dunno, 90s? Sunny side pot temps at 