For Normandy there is not much to think about. A clear vote for option 2. The G43 was very scarce and in my opinion has no place in the spawn menu, not even as a limited spawnclass.
If the map doesn't work without it, it is the maps problem. Design the maps that they work with the weapons historically used at the time the map is set.
Talking about 0.4 ratio on limited kits. They are useless, even on late war maps when those weapons were more common. You always have to look at the whole thing. On the example of Lüttich you see that with a 0.4 ratio on a full server you will have 14 G43. Add 9 MP40, 4 MG42 and 4 Panzerfausts. That sums up to 31 players being able to use one of the limited kits. Where is the limitation?
In my opinion the ratio on any limited spawnclass should never exceed 1.6 which on a full server allows 6 people to use that class. Exception could of course be made on maps that feature units, it is known that they were especially well equipped.
When the G43 is used as spawnclass on later maps it should in my opinion not replace the regular K98 rifleman. To put it in the scout class certainly is a option but I have my doubts. If you put it there you have to limit the class.
Can those few people who will get that class provide artillery with enough targets? I think 99% of the players who choose it do so because they want better firepower, not the ability to spot targets.
Another thing I could imagine is removing the engineer class from the spawn menu and replace it with the limited G43 class that we have now. In my opinion the engineer is not really needed on the later maps. His mines already got removed for Normandy because of the maps being much more narrow.
The Geballte Ladung he has now is of course fun but in the matter of gameplay rather insignificant. The only thing that is important on the engineer is the wrench. But that could easily be issued by pickup ammokits at static defences and pickup pilot and tanker kits at vehiclespawns.
Something like this: