I suspect it went on way to heavy and is now curing unevenly. I also suspect that it hasn't fully cured (smell it and I bet you still smell the thinner). Once it has thoroughly cured you can probably sand down the high spots and it may be OK. If you try to sand it before it has thoroughly cured the uncured paint will just roll up on the sandpaper. Use progressively finer grades of sandpaper and finish up with about a wet sanding using 1600 grit or so. Since you plan to spray Alclad over it, it needs to be really smooth.
Next time you use rattle can paint (especially Testors!) sit it in a pan of warm (NOT HOT!) water for a few minutes and it will spray thinner and more evenly.
Alclad is a laquer. You can spray laquer over laquer, enamel, or acrylic as long as the underlying coat is THOROUGHLY cured and the initial coats are sprayed on very thinly.
Word of advice ... shortcuts seldom work on models. Been there, done that, paid the price many times over. I never seem to learn.