OKAY 2 parts, PLA adhesion issue  

OKAY 2 parts, PLA adhesion issue

What else can I try in order to achieve a successful print?

I am attempting to print parts for the OKAY 2 synth project at https://www.thingiverse.com/thing:2760653
I am having trouble printing the larger parts (the top and bottom of the case, the keys, the OKAY letters) because the left and right edges of the parts keep lifting off off the PEI sheet after two or three layers.

In particular, I'm having trouble printing the top of the enclosure. The part just about spans the entire heat bed of the MK2/S. The part keep lifting from the head bed on the left side, especially toward the back.

I'm using iPrint 3D green PLA which I've had great success with for smaller prints.
nozzle temp is 210 C.
heat bed temp is 65 C.
ambient temp is around 21 C.
Printing speed is set to 30%.

I tried adjusting the print levelling offsets for left = -30, back = -10, then wiping the PEI with acetone. This resulting in a reasonable print of the enclosure bottom, though the corners did lift somewhat, but not enough to make the print unusable. The enclosure top still lifts early at the left edge.

I tried adjusting the temperature settings to nozzle temp 220 C and heat bed 75 C, but the left side of the enclosure top lifted early again.
I've tried adding a 7mm brim. Results were similar, though the PLA lifted in a different pattern.

I've read that PLA warping occurs when the heat bed temperature is too high.
But I've also ready that PEI adheres more effectively at warming temperatures.

Which of these contradictory suggestions is the greater factor?
What should I try next?
Will a lower bed temperature be more likely to get the PLA to stick?
I've been disappointed with glue stick when printing PLA. Would anyone recommend hair spray?
Would I have better results if I just wait for my MK2.5 upgrade to be sent, and use the textured PEI sheet?