It's not just the spring that controls secondary opening, the kill bleed also has a part in when the end carbs open.
Basically, the kill bleed controls the RPM when they start to open, the spring controls the opening rate (how long they take to fully open).

It's doubtful your bog/surge problem is the opening rate, it most likley one of these;
Not enough accelerator pump shot
Not enough initial timing
Sticking throttle plates
Clogged air bleeds or main circuits in the carbs