Di Mitri, S. Aicheler, M. Aksoy, A. Alesini, D. Burt, G. Castañeda Cortés, H.M. Clarke, J.A. Croia, M. D’Auria, G. Diomede, M. Dunning, D.J. Ferrario, M. Gallo, A. Giribono, A. Goryashko, V.A. Latina, A. Mostacci, A. Nguyen, F. Rochow, R.A. Scifo, J. Spataro, B. Thompson, N. Vaccarezza, C. Vannozzi, A. Wu, X.W. Wuensch, W. JACoW Publishing Geneva, Switzerland The CompactLight European consortium is designing a state-of-the-art X-ray free-electron laser driven by radiofrequency X-band technology. Rooted in experimental data on photo-injector performance in the recent literature, this study estimates analytically and numerically the performance of the CompactLight delivery system for bunch charges in the range 75-300 pC. Space-charge forces in the injector, linac transverse wakefield, and coherent synchrotron radiation in bunch compressors are all taken into account. The study confirms efficient lasing in the soft X-rays regime with pulse energies up to hundreds of microjoules at repetition rates as high as 1 kHz.