The efficiency and uniformity of photon echoes are investigated in optical coherent transient sequences using temporally overlapped linear frequency-chirped programming pulses. Distortions in the power spectrum of the programming pulses due to edge effects are found to cause fluctuations in echo efficiency as a function of echo time delay. Smoothing the edges of the programming pulse envelopes is found to significantly reduce distortion in the power spectrum of the pulses, which leads to echoes that are both more efficient and more uniform than those generated by pulses without smoothed edges. The effect of programming pulse strength on echo efficiency and uniformity is shown and discussed through simulations for an optically thin medium and through experiment in ${\mathrm{Tm}}^{3+}:\mathrm{YAG}$ at $4\mathrm{K}$ .