My 2 cents worth.....
The rule when it comes to paints and which you can use together on the same surface is:
Acrylic can go over Enamel, Enamel can go over Lacquer, but none are supposed to be used in reverse order.
(Eg: Enamel over acrylic, Lacquer over Acrylic or Enamel are big nono's.)
Now saying that, I have used Gloss & Matt Clear Lacquers over Enamel paint using several very light coats of lacquer and never had a problem, but Enamel paint is a lot tougher paint than acrylic paint.
(I did also wait for the Enamel paint to not just dry, but to "Cure" properly before using the Lacquer over it.)
I don't use Acrylic, only Enamel, so I can't say how I found the way Lacquer and Acrylic reacted when used together.
(Check to see if its actually a "Lacquer" type of clear coat.)
You are using acrylic paint so I would be very careful when using those clear coats mate.
BTW, Tamiya Acrylic
X-21 Flat Base is NOT a "Clear Coat", its actually for adding to a
Gloss Acrylic paint to turn it into a
Matt Acrylic paint.
Cheers,
Dave