Have you tried the ER4s? I own both and find the ER4s much more isolating (and for me, as a mainly classical listener, a bunch cleaner sound).

Yes, I did, I used to own ER4s. To be fair, I'm not using the integrated tips and instead use Comply tips.

It may have been that my ears just seal better using foam than with the three flange oddity Etymotic puts on these?

I do agree the Etymotics sound better out of the box, but after using AutoEQ they sound pretty similar.

Oh yah, the silicone tips aren't that isolating. The foam ones, however, are magic.