Two-Way Satellite Time and Frequency Transfer (TWSTFT) technique is a highly efficient technique to compare remote ground atomic clocks using radio links in the microwave domain. Its main advantage is based on a direct comparison approach, in active mode, which reduces very significantly the systematic errors in measurement using the principle of two-way paths. This technique has demonstrated outstanding performance in the construction of the TAI/UTC, calculated and published monthly by the BIPM, thanks to the remarkable efforts of the CCTF working group on TWSTFT. However, this method is complicated by its operation and its scope in the microwave spectrum, requiring a solid installation and full control over the entire chain propagation (electromagnetic losses, mismatches, connections) in the various component parts of the earth stations. This presentation will attempt to show how the optimal configuration in terms of ultimate performance of an earth station can be reached, based on a rigorous evaluation of the intrinsic characteristics of the system (earth station, satellite link).