You're not gonna like this......
This may not be the answer that you want to hear but, usually you are far better off finding the handgun that shoots exactly where YOU LOOK rather that trying to adapt yourself to where one of your handguns wants to shoot.
I get rid of any handguns that do not point shoot correctly for me.
I have been instinctive shooting for a long time and there are some firearms that just do not suit me and they refuse to "point shoot" accurately for me ~ while others are dead on the money.
Were I you....I would honestly go gun shopping again.
IF...you are really serious about true point shooting.
That is my honest answer UNLESS that is the handgun that you choose to "point shoot" with forever.
You are really going to subliminally mess yourself up with your Para & your PT99 if you force adapt the location of your instinctive hits with your GLOCK.
Just my opinion.