I use no screw and no tape on the cobblestone Mantis protector. It's held with just the one center screw. I bend the protector slightly so that it is snug against the edge. I've had no problems in 500 plays.

Buy directly from Cliffy. It's a manual process (email him for a Paypal invoice), but it works.

www.passionforpinball.com

You can install the Mantis later. Installing the Mantis is generally difficult. Also, installing both the Pinbits and the Mantis is a bit overkill. If I understand correctly, you also got a mylar shaped to fit under the Pinbits? If so, you are truly overdoing it by installing a Pinbits over a mylar and with a Mantis. This will be the first time I've heard of someone installing two forms of protection, never mind three, in one place.

Mylar is generally for flat areas to help prevent wear from a ball repeatedly rolling over the flat area, such as between the pop bumpers. Mylar is not generally used to prevent impact wear at holes, for example. Cliffy and Mantis protectors help prevent impact wear at the edges of wood cutouts.

Does the metal protector come with an adhesive back?

It's your call. Personally, I do not install protectors that cannot be reversed. I do not peel off the release paper on Cliffy's that have adhesive (such as slot protectors) and I have not had a problem. I have not tried the MM Merlin protector from Pinbits, but it may be worth trying without the adhesive.

I'm biased against mylar in a home use machine, so I'm probably not much help with advice on that.