Mattress Forum

Generally speaking, no.

• Two 3" cores are easier to handle than one 6" core.
• Two 3" cores of the same density should behave as one 6" core of the same density.  Except, Dunlop (vs. Talalay) tends to mold less homogenous top-to-bottom, being more dense on one side... so such a density variation in a 6" core would not behave exactly as such a variation in two 3" cores (I suspect the later would feel slightly more firm).
• Two 3" cores allow choosing two firmness ratings for a progressive firmness; this can't be done with one 6" core... except one might reason that a 6" Dunlop core would have a progressive firmness due to it's inherent density variation top-to-bottom.
• Two 3" cores allows mixing or matching or flipping their firmness ratings at perhaps only the additional expense of one 3" core vs. swapping out an entire 6" core to make a change.  That said, I feel it is probably better to keep the firmer core on the bottom.

A side sleeper needs a topper (depth and firmness) that allows hip and shoulder to plunge/settle before reaching firm support too soon.  This can be achieved with 3-3-3 layers of progressive firmness... 28-36-44 Talalay would be cushion-firm for a side sleeper, but one can get use to it.

A front sleeper needs a topper that is not too deep/soft such that it sags the back before reaching firm core support.  The above 28-36-44 Talalay can provide this.

The two needs can be at odds, depending upon how big and heavy the two sleepers are.  If they are not at extremes, then one-piece cores can work.  Otherwise, you might have to split the cores for his and her side.  He might prefer 28-36-44; she might prefer 28-32-36, particularly when she is the side sleeper, which is more common.

But in your case, being a side sleeper would tend to lesson the need for more firmness to support a bigger, heavier person.  And her being a front sleeper would tend to increase the need for firmness despite being a smaller, lighter person.  So, your needs naturally differ but they tend to converge, and may not require split cores.

GK