The task is not easy. Find the book by Matthaei, Young, Jones: Microwave Filters and Coupling Structures. There are many examples of filter design and comparisons of real results with calculations.
Pseudo-HPF? You mean actually a BPF but used as HPF?
Normally Coupling Matrix is used to "describe" a BPF. The matrix tells the resonator offsets and coupling connection between resonators. Mathematircally, the coupling matrix elements are related to its corresponding lowpass prototype "g-table". Once you get the coupling matrix, you realize the physical filter (microstrip, waveguide, SIW....) based on the matrix.