In inertial fusion shock ignition, separation of the stages of fuel compression and hot spot creation introduces some degree of design flexibility. A lower implosion velocity can be compensated for by a more intense ignition pulse. Flexibility increases with target (and driver) size and allows for a compromise between energy gain and risk reduction. Having designed a reference ignition target, we have developed an analytical model for (up)-scaling targets as a function of laser energy, while keeping under control parameters related to hydro- and plasma instabilities. Detailed one-dimensional simulations confirm the model and generate gain curves. Options for increasing target robustness are also discussed. The previous results apply to UV laser light (with wavelength lambda = 0.35 mu m). We also show that our scaling model can be used in the design of targets driven by green laser light (lambda = 0.53 mu m).