I've been home-etching "stuff" for over 30 years. I have done electronic circuit boards, brass and nickel-silver (both single and double side). My latest project was very small. Side mirrors for a N scale FedEx Dodge Sprinter van.
Those were single-side etched out of 0.005" brass sheet. I use ferric-chloride etchant but even with warming it up to about 100 deg. F it still took quite along time (IIRC, couple of hours). I use spray-on photo resist but some day I like to try the photo resist film and a laminator. On single-sided sheets I spray a generic primer to protect the metal.
I draw my artwork in Corel Draw. In the past I used to get it printed on a phototypesetter as a black artwork on clear film. Nowadays on my last couple of projects I printed my artwork on transparency using my Alps printer. There are some tricks involved to get it opaque enough and the artwork is fragile, but it works.
I never used a peel-n-stick film and I suspect that alignment would be problematic for double-sided etching. I make my double-sided artwork printout larger than the sheet to be etched and I print targets on both artworks (outside of the etched sheet). Then I sandwich the metal sheet (coated on both sides with photo resist) between the artwork transparencies (aligning the targets). Then I sandwich that sandwich between 2 sheets of glass, clamping them with "bulldog" spring paper clips. Geez, all those sandwiches make me hungry!
I then expose each side to UV light and then develop the metal sheet.
When etching double sided piece, make sure to put some spacers under the piece so that it doesn't rest on the bottom (that will cause the bottom not to etch evenly).
In your case I think that single-sided etching will work (unless you want to add some relief-etched texture to your parts). But then the parts will be only 0.0025" thick with the details being 0.005". In a single sided etching there will also be undercutting around each etched opening which will be close to the thickness of the etched part.
But etching stuff is a pain in the
! With professional etching services becoming quite affordable (and your pieces being relatively large), have you considered sending your artwork to be etched by a industrial etcher like
http://www.ppdltd.com ? When I will have a larger project (larger than N scale side view mirrors) I will seriously consider using them for the job (especially since they accept Corel Draw artwork).
