next step for bud development w/ hi heat & low humid conditions

Help
I am constrained by High heat and low humidity - live in the desert
I vegged 6 large on a MH 500w then to 750W & switched to LED to flower ( too much heat to run a 1000w HPS) vegged well in 7weeks in these conditions.

Conditions

• around 78 to 82 in tent
• humidity 22 percent max
• MH 500w
  
• Botonicare formula w/ calmag approx 1100 ppm in
  RO
• Coco coir

I now have 6 large 40 inches bent over & semi lolipopped in 4 x 4 tent

Switched to flower 2 weeks ago

changed to these conditions:

• LED varaspectra 1200w HPS equivalent ( actual watts about 550)
• botonicare bloom formula w calmag sup 1000 ppm in RO water

I developed many bud sites high and low

Question is what is my next most cost effective and / or productive step to get big buds given my constraints of high heat and low humidity.

First grow
All suggestions greatly appreciated.

You I've always heard that the low humidity like that increases resin, like the plants way of not loosing too much water so it makes more resin to create like a sheild, have you thought of making concentrate

CO2 supplementation but I'm guessing you are already running high air exchange so that may not be an option. Buds tend to be a little more airy in those conditions. Probably not a big deal, might as well just see how they do.