Hi Wynand, glad to be of assistance.
I have about 30 nuts on my rack which includes 6 hexes.
Trust the BD nuts, they are of the best, if not the best nuts on the market. They place well and don't stick too easily making retrieval simpler for the second. Try avoid Wild Country Rocks and DMM Wallnuts in the small sizes as they are tough to place and stick very badly. The big DMM Wallnuts are good and place well in gnarly cracks.
Start out with BD nuts sizes 3-12 then add some hexes to extend the range. If you find you place a lot of nuts then double up on those sizes. Don't worry about micro-nuts until you think you are ready to trust those tiny things, they are a whole different story.
I have BD hexes sizes 4-9 on my rack. This hex range covers the cam sizes #0.4-#3. Hexes are bomber when placed correctly, as with any pro but take a little getting used to. Your climbing buddies will also not find it hard to locate you in the mountains. Just jingle a couple of hexes around to see what I mean.
The BD hexes are availible on wires but mine are still of the old type where you had to add your own \"spectra\" cord. My hexes are my most trusted gear and have never popped on a fall. (touch wood)
The Wild Country \"rockcentrics\" are also great, they have a good range and fit easier into cracks than the BD hexes. This also means that they stick easily and can be a bugger to get out again. They come with Dyneema tape and the colour coding makes it easy to distinguish the sizes.
Learning to use hexes can be easy if you spend a bit of time reading the pamphlet that comes with the gear and playing around at the base of the crags, testing the kit out.
Most crags around the country take good hex placements.
Good skill with nuts and hexes cannot replace any cam.