For what it's worth I have wired up frames for foundationless without using eyelets. It will cut into the frame a little over time but it isn't a big deal. If the wire does loosen slightly (due to cutting into the frame) before you put it into the hive you can grab the wire on the outside of the frame with needle nose pliers and twist a little to tighten it back up. Works for me.
I've had mixed results with monofilament, some hives build right over it, but I've had a few cut it out so I'm going with wire now.
I've had mixed results with monofilament, some hives build right over it, but I've had a few cut it out so I'm going with wire now.