Hi,
I learned on a Katana and now have 80hrs on type (not much in the great scheme of things tho'). IMHO it doesn't really add a great deal to your workload, although it is important to ensure that you have the prop fully forward when on finals just in case you have to go-around. What I do is put the prop forward when turning base - pretty much at the same point when I'm thinking about throttling back.
You should be ok once you've had the suitable time on any differences training. Go for it.
Edited to add that the DA20 does indeed have separate prop and throttle levers. (But there's no mixture control to 'worry' about, so at least that eases the workload slightly).
C23