Is this the same ticket that you posted about here? If so, please keep all of your posts in the same thread.
You can appeal a final judgement of conviction, if your case has reached that stage. Have you already gone to trial and been found guilty? If so, you need to read about appeals in infraction cases here.
The public prosecutor doesn't attend traffic trials in California.
Qualification of an expert witness is reviewable under the abuse of discretion standard. This means that you're only likely to have such a ruling reversed if the expert obviously lacks qualification, and the judge ruled that the witness was qualified. An objection is required to challenge an expert's qualifications. If you failed to object, you've forfeited this on appeal. For scientific evidence, once the court rules that the method is admissible, variations in technique or procedure go to the weight of the evidence and not its admissibility. Because the weight of the evidence is part of the finding of fact, it's subject to the substantial evidence standard of review. This means that the appellate court looks at the evidence in a light most favorable to the prosecution in order to determine if any reasonable trier of fact could have found the essential elements without a reasonable doubt. This means that as long as the appellate court can find some reason that favors the prosecution in the evidence then you won't get a reversal on this either.

