I would get a mix of LR. I especially like a little bit of Tonga branching LR to help make arches & bridges within the rockwork. When I aquascape my reef tank, I set a few larger pieces on the bottom to act as a solid foundation & then I wedge in the other smaller/longer pieces to help form caves & caverns for my fish to swim through. I also try to add some flatter pieces to give me shelves for putting my corals on.
Aquascaping is really in the eye of the beholder & what one person likes may not be what looks nice to you. By having an "open" structure like described above, it also gives the anemone many choices as to where it wants to plant its foot & stick its "head" out. It also allows you to get higher up towards the light without overloading the tank with too much LR.
Is the tank 3' or 4" long? Keeping an anemone happy will usually require MH lighting & trying to save money by buying cheaper lighting will end up costing you in the future when you almost inevitably upgrade (speaking frim experience here
) Like the others mentioned, plan ahead & try to do it right the first time, because constant upgrading will lead to a closet full of unused equipment & a big hole in the wallet. On the other hand, if you already have a simple fluorescent fixture, that will work in the Fowlr until you are ready for an anemone or corals.
Having a sump is good because it gives you more choices when it comes to skimmers. Others can give you more recommendations about skimmers but I'm happy with my (HOB) Remora Pro & (non-HOB) Tunze.
Remember that most manufacturers waaay over exaggerate the capacity of their skimmers, especially Prisms/Prism Pros & SeaClones.
A pair of Cleaner/Peppermint/Fire shrimp & some snails are almost always good tankmates for clowns. For hermits, I find blue-legged & neon blue-legged are the best.
Yellow watchman gobies, clown gobies, lawn mower blennies, and other small hardy bottom-dwellers add some extra life & interest to a tank.
A pair of Bangaii cardinals (males have longer dorsal fins) or a trio of Chromis can help add movement & colour to the mid-water region.
BTW, clowns do not need anemones to survive. It is great to witness the symbiotic relationship, but anemones are not the easiest to keep alive in captivity, I have found clowns hosting in colts, rhodactis mushrooms, finger leathers & toadstool corals, all of which are hardier & require less light. If you go this route, 96w PCs or VHO lighting would be fine. However, if you like high light requiring corals/clams, then definitely invest in the MH system.
Hope you had fun reading this essay
Anthony