I recommend using some busses, and multiple layers to create the total effect you want for the instance of the bass.
...which is pretty much what I said in that comment you wouldn't suggest. 
no, you suggested frequency splitting and duplicating one signal, not creating new layers.
unless you mean something different and it didn't come across that well.
But, the idea of what you said is correct, i just don't know if the implementation was correct, even though you may have the idea in your mind.
it's like having a sub bass layer, with a mid bass layer, and a high bass layer. Rather than having one bass layer that's split between the frequency that i've described (i've done it this way and it never got me any where close to what i wanted).
*edit* the only part that you did say that you add a layer is in the "lead spectrum", the rest i took it as "just duplicate what you already have and filter".
and to my experience, you can get a much cleaner sound by creating new layers and having them fit, than just duplicating and splitting frequencies.
the differences in tone and timbre is what comes across as having a big huge layer, with many things to listen to at once.
also it's good to have some automation when making your big bass business.
*DOUBLE EDIT* my initial post was rought with assumption and didn't penetrate the truth. These posts are good advice, but still doesn't address the stereo side of things. I think the break down was that, you might need to have a filtered sound in a specific range, that isn't apart of the original idea. Like my gripe with duplication, which may work but with variables added to where it's not a duplication, you'll need to make it different sounding and still have it fit with in the context you're looking for.