I would start with Mode one for a couple of days but I am disturbed that your zapper does not offer 2.5 kHz continuous.
Mode 1 = 30 kHz sequenced (7-20-7-20 min on/off) for 2-3 days
Then add 2.5 kHz but I feel that the 2.5 kHz pulsed is not as effective as a continuous signal would be.
Day 3 or 4 I would add Mode 4 = 2.5 kHz pulsed (1 second on, 1 second off) for (14-20-14-20-14)
About Day 6 or 7 I would change the Mode 1 session to Mode 2 = 30 kHz continuous at a sequence of (14-20-14-20-14-20-14) and also use the same sequence for the 2.5 kHz.
After a few more days, I would also add another 14 min at 2.5 kHz every 2 to 4 hours.
This is what I would do and if it is a zapper with a good signal, I would expect the problems to start disappearing.
I would also use the copper paddles with the augmentation copper footpads.