Hi bfcarbon,
I know it has been a while since you were looking into this but, if you are still looking, you could also try out the automatic nesting software at
www.mynesting.com
It is completely free to download/use and runs on your own PC like "normal" nesting software. There will eventually be a small fee each time you choose to export a completed nest (a few $) but it is currently free for exporting as well.
You can see the nest before making the decision to export so, if you're not happy with the results, you can tweak settings and renest or simply exit the software and there is no charge at all.
It only works with dxf files at the moment but if you could convert the .plt files into .dxf then MyNesting could be ideal.
Let me know if you have any questions or want any advice
info@mynesting.com