I have experience with them, but not with trying to advance the timing. It wouldn’t surprise me that they have fixed timing...I was looking at the signal generator, and wondered how it advanced the timing, since there is nothing mechanical...
Anyway, there are dirt cheap “racing” cdi’s that claim to advance the timing at higher rpm, even showing a graph right on the label. Again, it could be true...otherwise I doubt they’d rev up very high, and they go over 8k rpm with little effort with one on it. Maybe I’ll compare it without...or check it with a timing light and see if it advances at all.
OOracing could probably give you a definitive answer as to whether or not the cdi advances the spark or not. Otherwise I doubt they’d be hitting 12k rpm on the things.
This:
https://www.ooracing.com/tuningTips.htm
Seems to suggest that the CDI unit does, in fact, advance the timing based on RPM. That's even a diagram of the same basic CDI unit that my engine came with.
PS: Those 110cc are quite limited on power. Might work fine for an areo modded bike, but you won't get past 50mph on an unmodded one. That's if speed is a factor in your purpose. Look for 125cc+ if you need more power, preferably with the large valves. Of course that might kill your MPGs...