External Walbro Pump - Which washers for fittings?

[88turbobird]

I'm installing an external Walbro pump on my 88TC and was wondering what type of washers people have used for the pump fittings. The fittings I bought came with what appear to be plastic (PTFE??) washers. Are these good or should I pick up some aluminum crush washers? 

[Stinger]

We use copper crush washers, PTFI are fine, as are aluminum.

[88turbobird]

Thank you; I have a bunch of copper crush washers so will go with those