Any one using Freeroute? I have a question

[julian1]

I know the general advice is to avoid the autorouter, but I have also read enough contrary opinion suggesting that Freeroute actually does a pretty reasonable job.

Before I go about building the Java app and exporting and importing the specctra design files, I would be interested if anyone knows -

If it is possible to constrain the routing of netlists to specific layers? I have a four layer board, with dual power supplies and would like the IC supplies/ and decoupling to be immediately routed to the reference planes with vias. 

Also, is it possible to specify that signal routing should only use the outside layers?

[julian1]

To answer my own question - It looks like I can de-select routing for the middle reference layers, so it only routes top and bottom. Then re-import back into kicad and do the power and gnd vias manually.