Also new but I've been going through much the same sort of thinking.
I think the reason that the theoretical BPF frequencies are too high is because there is parasitic capacitance in the circuit as well as that provided by the capacitors.
I tried working backwards from the frequency and inductance to get the capacitance and it was 30 to 35pF higher than the capacitance value.
I was looking at the QMX which has an unused position on the BPF multiplexer and 30pF + 32pF parasitic capacitance and an extra 14 turn tap on the inductor gave about 19MHz which could be useful for adding the 17m and 15m bands.
Chris, G5CTH
