Aw, am sorry you've been under the weather, and hoping you're feeling better soon.
We use Catsan clumping too or PAH own clumping brand, and find it really good. We don't use that much all told.
We scoop daily, but I don't waste much.
I think the trick to stopping litter from smelling is to use a deep layer of litter. It doesn't penetrate through to the base then, so the smells are less.
Having said that, some cats' excretions are more pungent than others.
You could also try taking the hood off the tray if it's removable, as sometimes this can exacerbate the smell (even where a filter is in place)
Malt has a problem with peeing over the edge of the tray at times, but we solved that by putting puppy pads under the tray which helps reduce the worst of the smells until we get up and can change the pad.