HTWingNut

edit: someone else already posted this gif
it's too good not to be repeated tho

I dunno. I've been doing it for 25+ years and never found much difference short of gobbing it on or putting way too little. There's a lot more room for error than people make it out to be. I've even managed lots of laptops with thermal paste where it's more critical to get full coverage since there is never an IHS.
 
Best recommendation is to apply liberally like in that gif.

NEVER do this. You'll become the "bitch" of the family who always work for free.
Always charge something, even if it's just $10 or $20. Never work for free, unless it's a very quick fix. Anything that take more than a few minutes to do, charge for it.
 
Not to mention, they will always come to you whenever they have an issue with it. If 2 years down the line they have a problem, they will blame you for it, even if you have zero responsibility for it, just because you're the one who initially "fixed" it, so obviously it should be working 100% always right? That's how it is with family. Especially if you do it for free.

now make sure windows under display adapter properties is running at the new refresh rate

Thats the issue, DISABLE that.
 
Your monitor has in built OC in the OSD.

Yes, but those individual units are ridiculously expensive.  I can't even bring myself to post any links.  What I'd recommend is two separate single-monitor arms with the range of motion that you need.  I haven't used this model, but it serves as an example.