Heidelberg OHT 10"x 15" Windmill

Anybody can help with adjusting printing pressure on a 10"x 15" windmill? The pressure is more on the top. This is visible when we run a microperf job. Overall pressure adjustment is working fine with impression on/off handle.
Thanks for help.

 

Reduce pressure with the impression handle until it's even across the microperf, then if it's not enough to perforate, add packing to the platen or behind the forme.

 

Thank you for the help.

 

You can always add, locally packing via tissue paper or sticky tape, behind form without altering handle pressure -same thing what notagooner said-

 

I have a problem with 13x18 windmill. The grippers are touching the die cut jacket and not possible to stick the matrix. I hope to hear from you soon.