PSEUDO REVERB. A SOLUTION.
You would like to give some nice atmosphere to your lead, but there is not enough DSP power to load a Reverb, you have just a little bit left, dam! What can you do? Simple! So simple that I probably shouldn't be writing it.
Load a Sample Player, choose a spacious, atmospheric sound that mixes well with your leading sound and put both devices onto the same MIDI channel. Now without a reverb you have, quite closed, the effect you were looking for.