The 2400 is the competitor, the 4200 is one of the newly introduced elite models... which do you mean?
I've not had any problems with the level of cushion on the tongues in my 3900's (the old Elite Supreme). That said, I need a new pair of boots myself now but since they've discontinued the 3900 and the tongues on the 4200 and 4500 both have latex foam (I'm allergic), I'm looking at other options since with the split width I need, two changes makes it considered a full custom order, and a custom from Jackson rivals buying a custom pair from any other maker, and if I am going full custom I'd rather work with a fitter in person to make sure I get exactly what I want/need rather than an approximation of a discontinued stock boot.
I would strongly suggest the bunga lace bite pads to get you through until you can get new boots... you need something to protect that area.