Congrats, kcfcycle!
ort
I have a Z125 too! not long ago, picked it up (used) to specifically run with the Grom's (and alike). I call mine the Grom Chaser
Although, I'm still in transition of preparing it to race with (gearing and after-market exhaust [Yosh RS-2]). I've only got 1 track day on it. Time hasn't been on my side, these days. Wanted to attend this last race at Dixon, but the Z isn't quite ready.
Attending mini-moto track days is pretty informal - just show up with your bike (and track gear), sign the liability waiver, pay your track day fee, ride and have fun! Just be sure to do basic bike prep (see below or see Track Day thread)
As for prep, I removed the stock headlamp assembly (really easy; remove 2 screws and undo wiring), removed the rear eliminator kit (4 screws), un-plugged the rear brake light, and removed mirrors. That easy and simple!
As for on-line track day or race schedule, Sonoma has one, as you know. Stockton lil 99 may have one too. But, I get all my info from their FB group page, NorCal Mini Racers.
I think Dixon has one specific to karts (Kinsmen Kart Club), but not Moto's. Although, they announce their Moto track day activity on their FB group page as well. At times, it can be within two days of the up-coming weekend. cost is typically $40, per rider.
Stockton is the only track that offers membership for riders, as Junkie stated previously - any time access. If attending on a scheduled Open Track Day, member track day fee is $30, non-members is $40.
As for sessions, Sonoma typically has two - Karts and Moto's. Rarely, will they break it up any more than that, that I'm aware of. Stockton and Dixon will break into sessions (A, B and C), depending on attendance, displacement differences and rider experience, to keep the track time fun and safe for all.
I typically will do my best to pass it along here (and supermoto forum), as I know not everyone is on FB.
As for bike prep. See the Track Day thread (sticky) for general prep. Stockton and Dixon are not as strict as Sonoma. However, do your diligence to comply to be within general / typical bike prep, as suggested within the Track Day thread.
See you at the track soon :ride