This is what I have decided to do:

I like the stock on my 25-06 and after looking at the pictures on the NEF website again I have concluded that the stock is the same for the super lite and the regular synthetic handi rifle. Only the youth model gets a different stock (and the survival model).

The difference between the superlight (only available in .22 hornet, .223, and .243) and the regular synthetic version is the barrel. Superlites have 20 vs. 22 inch barrels and they are turned down. IMO, from shooting my .223 superlite barrel vs. my 25-06 26 inch ultra barrel (fits on the same frame) the super lite is a disadvantage. They are hard to shoot offhand, the barrel is too light IMO.

So I am going to get the regular synthetic .243. It will have a 22 inch barrel which is better than the 20 inch superlite barrel, it will have the same stock as my 25-06. Also, I can later teach my kid to hunt with it and even put on the .223 superlite barrel if needed.

I think with Hornady SST interlock bullets .243 will be fine and it should be nice to shoot. Hornady makes a SST in 95 grains for 243.

My 25-06 is too barrel heavy to teach a kid to hunt with. Also, it is always nice to have an excuse to buy another gun. And I don't have a .243. Rounds it out nicely, because I have centerfires in .223, 25-06, .308 and 30-06.