L tophat adds 2.57L, ontop of it's base volume of 8.2L, makes it 10.77L. If you use a S+M top hat it's only 10.09 to 10.10L.
Current C4-SFX is 9.85L, adding a liter ontop of that puts it at 10.85L, or 10.6L if it's only 0.75L addition.
That would make C4-SFX an extreme niche, only for those who...