The main purpose of a compressor is to level out the sound; this is needed for a singer with bad mic technique where the microphone is hand held and the performer keeps moving the mic away from his/her mouth in every possible direction and distance as if they were using the mic as a weight to exercise their arm muscles! With a microphone held on a mic stand the performer keeps turning his head away from the mic or keeps moving and dancing away from the mic... Trust me, this happens way too often.
With proper mic technique a vocalist mostly stays on the mic and pulls away from it as needed when reaching a crescendo in loud passages of a song. With the L1 system you get to really hear how your voice is amplified and you get to monitor how you are controlling your voice; I really appreciate being in the sound field of an L1 while I'm singing and having the ability to acoustically mix my voice with my guitar (or with my duo partner's voice when performing with my duo).
Some vocalists use a tube compressor for their voice mostly for the tube sound qualities and sometimes for the crunch it adds to the vocal but this is very rare and not worth the expense unless you're rolling in money and already own too much swamp land!! The T1 does not have a tube compressor and doesn't need one.
Not using a compressor totally frees a vocalist who is using an L1 system to use the complete dynamic range available (a compressor inherently limits the dynamic range). Many members of this community have commented over the years on how much they have been able to improve their vocal performance by simply using the L1; many comments predate the arrival of the T1.
I highly recommend not using the compressor option for your vocals. I would instead take time tweak the zEQ to get the tone of your voice to shine through. I would also experiment with the different reverb options and possibly add a bit of delay. Of course, reverb and delay should be used very sparingly as too much reverb can cause problems with feedback. Most often the room provides sufficient amounts of natural reverb, especially with an L1.
The bottom line is that compression will not bring a noticeable benefit to your voice, especially when proper mic technique will empower you in ways that a compressor can't!
I hope this is helpful,