I've seen the work lamont does with fiber lambda's - it's top quality. If it's your first time working with them they usually throw in the scan for free. Also, they should be amenable to pulling tests and showing you a range. They'll work with you before pulling the final - you just have to be persistent and not be bullied by them. Good luck.
PS... face mounting plexi is not necessary and adds a huge cost to mounting (again, lamont is trying to upwell you). Besides, it was a look that had it's day before the great recession and has since largely fallen out of favor. It can look garish with the wrong subject matter, IMHO.