I doubt you will need four coats.
Pine is about the hardness of Basswood which rarely needs more than 2 coats, 3 max.
Sand between each coat.
Paint may be applied directly over the Sealer for an acceptable finish, but will look better if primed first.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !