I'd definitely add more places for them to grab onto, even plastic plants until the macroalgae have a chance to settle in and take off. Then again, perhaps by the time the tank is ready for the SH you will have quite the garden growing.
One thought, be sure to lay out the rock in an open pattern to maximize water flow. In a dwarf SH environment water flow is usually very slow and gentle. The rock will further reduce water flow and could create a perfect environment for cyanobacteria or other unwanted algae nuisances. Keep the rockwork open to avoid having stagnant zones in the tank.
>Sarah