i've used a ton of reflective over the years! it cuts better with a 60-degree blade, but can be accomplished with a standard 45 with some extra pressure and slowing your speed. do test cuts til you get a good result! weed carefully - it tears easily and because of the reflective 'sandwich' you'll always see any little 'oops'
it's sometimes not fond of pulling off the backing...if that happens pull the backing away from the vinyl and tape instead of the vinyl off the backing. a higher tack tape works a little better, but if what you have is med tack, it can still be done.
the biggest tip i can give anybody dealing with reflective is.........don't put it directly on the surface! it's a nightmare to ever get it off cleanly! cut a shadow image of regular vinyl - probably black since it's going on his vehicle window - and lay it down first then the reflective over it. you won't really see the regular vinyl (unless of course the customer wants a visible outline, then use the color of their choice...) and you'll save yourself and/or your customer a ton of time and frustration when it's time to remove it!
good luck!
oh! oracal reflective is fine for the use you're intending. the only one i would absolutely, positively NOT recommend to anybody for any use whatsoever is avery.