As mentioned before, if you get larger denominations, just buy smaller items to break down the notes.
The downside is that you can end up with a pocketful of "shrapnel" by doing this. Depending on the amount, housekeeping will not say "no" if you leave a banknote and a pile of coins with a Thank You note at the end of your stay.
The Cape has recently had loads of rain, so the scenery should be great!
Happy travels!!