I would recommend the Laser 2003 XY from Sikora. The range of measurement is from .002" to .118". The accuracy is .25microns, which is less than the .3 you specified. This should work well for your application. I found a brochure for you on the Sikora website: www.sikora.net/products/laser-2000/_pdfs...re/LASER_2003_XY.pdf
I should note that I am an electrical engineer for the USA branch of Sikora. Feel free to send me any questions and I will answer them to the best of my abilities or will ask my colleagues in either the USA or at the headquarters in Germany.
Of course I am biased, but I believe that Sikora, being a technology-based, German company, holds very high standards in their measuring devices.
Best of luck with your project and let me know if I can serve you in any way.
Christian R. Ruiz
Field Service Engineer
Sikora International Corp
215 Prospect Park, Ste C
Peachtree City, GA 30269
Office: +1-770-486-1233 | Fax: +1-770-486-1201