Without affecting any security and isolation in Sandboxie?
I just want to protect the Sandboxie services from exploitation.

It's on Win7 64bit using EMET 3.5 Tech Release with ROP SEHOP and EAF ability.

Try it and see...? If it works, I doubt there'd be negative effects on Sandboxie's protection.

I haven't really had any desire to use EMET on Sandboxie itself. I don't think there's much/any concern about exploitation there. And if there was, I'd be more worried about stuff beyond EMET!