Which goes on first?

First, when would i want to use lacquer?  I build mostly WWII aircraft.

Doesn't matter... Most laquers go on dead flat and have to be buffed to a gloss... WW2 aircraft would benefit from laquers for the dead-flat finish..

Second, I thought it it was better to put enamels on top of acrylic, or am I reading the LEA backwards?

Doesn't matter which you start with, as long as you change between them.. If you painted the finish color with flat enamels, use acrylic gloss for decaling, and vise-versa..  Laquer wil attack enemel, but enamel won't attack laquer, generally speaking..  Also, If you paint a WW2 aircraft with gloss colors to begin with, you won't need the clear coat for decaling... You can paint & apply the decals, then apply an acrylic wash... Then a clear laquer flat coat, followed p with dry-brushing with enamels or acrylics...

Both Testor's Glosscoat and Dullcoat are clear laquers... I use those, along with Tree House Gloss, Satin, and Matte acrylic laquer, which are decidedly cheaper than Testor's & come in 13 oz cans rather than the 3.5 oz .. However, they can sometimes attack rattle-can enamels, especially the GLOSS "Wal-Mart" brands.. They seem to have no effect on flat enamels, at least not any I've used...

I've used automotive laquers on styrene many times, back when I was building cars.. I used regular enamel-based automotive primers first, then then applied the laquer with no ill effects... Applying the laquer over bare styrene in the same manner as enamels will ruin your model though.. You have to apply in very light, repeat coats, letting each coat flash (dry to the touch) before applying the next one.

One thing to keep in mind when applying clear laquers over enamels... You run a risk of the enamel wrinkling with too heavy a coat of clear laquer.. Mist coats only if you do that.. Also, some enamels will just plain not like laquers at all, so always do a test-shot...

As for the "LEA" rule, that's one I never pay attention to... General rule is to apply one type over another, ie; if you painted with enamel, then wash with acrylics, and vise-versa.. Then drybrush (you need to have a clear flat coat on to effectively drybrush) over your acrylic with enamel...  The reason is that you don't want the paint you're now applying to attack the one under it. 

Testor's Model Master Gloss and Dullcoats are laquers that are formulated for application over their enamels, so don't sweat those as you would other clear laquers... They even work well over bare styrene and won't attck it like say, an automotive-grade laquer would..But still keep in mind that they are laquers, and may not like the enamel you used if you used something other than Testor's enamels...  Test, test, test...

Hi Dan,

It's a "rule of thumb" for situations when you might apply paints of different type - it's not to say that you must use all three types

It's generally considered that the solvents used in lacquers are the most aggressive, followed by enamels and then acrylics.

For this reason, the general "rule of thumb" is that lacquers go on first, then enamels then acrylics. Solvents used in enamels don't (usually) affect lacquers and the solvents in acrylics don't (usually) affect either lacquers or enamels.

However, having said that, it's possible to apply lacquers over enamels or acrylics and enamels over acrylics, and many people do so successfully. One thing that you must always do when using multiple paint types is make sure that the previous coat of paint is fully cured (not just dry) before over coating with a different paint type.

PS: Many spray can paints (eg. Tamiya, including their spray primer) are "lacquers" - you may have used lacquers without realising it.

Don't know how old you are or how long you have been modeling, but many folks eventually get burned on on one subject and try a different genre.  Lacquer is popular with model car builders, sometimes used by civil aircraft modelers.