Homebrew PCBs

My pen plotter has run out of gas at 0.5 mil pitch.
Trying to make the transfer to toner transfer.
How do I get the gerber output to the laser printer?
I downloaded Viewmate.  Does an excellent job, but
insists on putting the plot in the center of the page.
And the free version is crippled so I can't save anything.

Is there a freeware gerber plotter that's less restricting?

I've been having good results plotting on copper with the lumocolor
313-2 pens.  If I could find a finer pen, I could avoid all this toner
stuff.  Ideas?

I'm finding little detailed information on the toner transfer
method.  Mountains of anecdotal stuff, but almost no data.

My iron is 450 degrees F.  Is that good? bad? ugly?  Time and pressure
data is elusive.  Yes, I can do all the experiments, but would be
nice to avoid most of that.

Thanks, mike