Carlos,
Use Future Floor Wax as a clear topcoat - it dries much thinner than Tamiya Clear and won't eat into other paints. As the above reply states, acrylic laquer is extremely "hot" and can (but not always) eat paint, kill decals and make your life a misery - not to mention bloody toxic.
Future is actually a really good alternative - just sparay it on full strength, use 3 or 4 very light dust coats, then nail it with a quick wet coat, then leave it for a couple of hours. If it needs a little mode gloss, then give it another wet coat.
You'll like it much better than the hot laquers.
Cheers,
LeeTree