What kind of lacquer do you recommend?
Personally I use Halfords' own-brand Acrylic Lacquer, which is sold by the car-and-bike-parts-and-accessories shop Halfords in the UK. Most of their stuff is pretty mediocre, but their spray primers and lacquers are excellent. I've heard good things about Krylon, but it's a brand we hardly see in the UK so I've not tried it.
I actually do laminate my cards:
They stack & shuffle nicely. The card backs are indistinguishable for my eyes.
Well, put it this way: all the glossy laminates I've tried - including self-adhesive and heat-applied - have resulted in cards which start to slide sideways if you put more than five or six of them in a stack.
(The reason I suggested that it may lead to cards which are distinguishable from the back is simply that self-adhesive laminates have a tendency to start to peel along cut lines with handling.)