Large dry bag vs saddle bags

Good day to all

I need some advice:

I am planning a Namibia trip ( my first on a bike) , now I have the following ???

Will have 2 crashbar bags,handle bar bag and tank bag as well.

2 Crash bar bags for tools and maintenaince items.
Handle bar bag for tyre repair kit seeing leavers are long
Tank bag for ods and ends and rainsuit

Which leaves the rest of my styff ( clothes,medic kit,cooking stove,camp stuff,toiletries )
Already have 20L dry bag for all the sleeping and camp stuff

Now the ?

Rather use a big dry bag and 20L dry bag on top for my camping gear basically vertically on rack and back seat (kle500) and not ridding with passenger.

Or leave top case on and buy saddle bags ( only thing is still need the racks )

I think the big duffel dry bag is going to be cheaper but which one will be best over all?

Thanks