Just get from handphone shop, ask them to paste easier. But don't get slaughtered if they are trying to sell you non reputable brands sp for a premium price. Then you're better off ordering from ecommerce platform yourself. Rule of thumb is Spigen cost $20/pc. No branding sp should cost much lesser than $20.
When I pasted the Spigen tg sp for my daughter's phone ytd night, I had a hard time wanting to take out some dust caught underneath the tg. Due to the 90 deg flushed body to the screen.
When you're at those high traffic accessories shop, they have lots of experience to do it 1 shot 1 kill. No dust. Casefactorie, p2omobile, mobilehardware, mobile square, whymobile, xgear...just to name a few.