Hi Tooth,
I am rather new at this stuff, but I think you will probably need a VCA module in addition to the LFO and envelope modules.
The way it works is that a LFO generates your waveform, and you connect it to a VCA to control its volume. Then you link up the envelope generator to the CV of the envelope stage so that when you trigger the envelope you get a sound out through the VCA.
Both the Tides and the Doepfer modules are two different styles of envelope generators, so you might just pick your fav if you want to have fewer parts. The Doepfer is more of a standard East-coast Moog-style signal ASDR, while the Tides is like a new West-coast thing that other fancy features behind menu-pushbutton selection options. The downside to the Tides is that you have to read the LEDs to know what function it is set to, the knobs change their purpose depending on the mode.
cg_funk