Average soliton propagation in periodically amplified soliton systems with stepwise varying fiber dispersion is studied. Optimal dispersion profiles are obtained by minimization of a simple and intuitively appealing perturbation function. At a given data rate, n-fold profiling is shown to permit n-fold extension of amplifier spacing. Equivalently, at a given amplifier spacing, it permits n√-fold increase of data rate. Hence, we demonstrate the feasibility of 40-Gbit/s operation over several hundred kilometers, using 5-ps solitons and 50-km amplifier spans.