The results of that pairing might be great. It might also be awful. The HE is sealed, while the combo is ported. They aren't specifically designed to work together. There could be phase and cancelation issues. (Again, they might sound fine.)
I would try this combination at a store before buying.
@AustinBasser WELCOME to TalkBass!
So, it's a long story (and one that we've covered here quite a bit). But the short version is this. TRY OUT any combination of cabs before buying an extension cab. Mixing different speaker sizes, and different cabinet designs, COULD result in LESS volume and terrible tone. Yes, you are reading that correctly. Two cabs COULD sound WORSE than one. (There's a lot of physics involved. But trust me.)
So try out any cab you plan to buy WITH your combo. That way you'll know before you buy if you have a great sounding combination.