You can double the modulation by just adding the same path&source&amount.
I’m sorry but that doesn’t work (at least on my unit Prophet 12 Module).
i’ve tried everything and the only improve was with 2 of the same lfos but it was a shy increment. when using the same lfo for the third time, there was no improve.
it doesn’t work with the modwheel neither envelopes.
I wonder if it’s because we’re modulating osc frequency and not osc pitch (there is no osc pitch as a modulation destination).
can you post a video or sound example?