use the lfo to modulate the filter cut-off lfo 2 has a dedicated slot for both filters, tempo sync the lfo, use a triangle or sine waveform.
Filter eg, you really have to play with the eg amount on the filter to get this right, however don;'t alway stick to positive methods, you can also set the eg to go negative so with a higher cut-off once it starts to affect it it will drop the cut-off.
If you want a long sweep of cut-off then simply make the rate of the lfo lower, like 4/1 the waveform will simply do one cycle every 4 bars
it's best to look at what destinations you have, the modmatrix is what I use because I'm not stuck with dedicated slots and I find it easier to think of, but when altering something common like the filter there is a slot so I use it. Subtle changes are some times better but I tend to just tweak as I'm playing that way you can hear what is going on.
Good thing about using the mod matrix and a lfo is you can say decrease the cut-off you can increase the res a little giving more squeel,