Heh... Oregon has all its voters registered. Easy peasy.
It is untrustworthy sorry.
Oregon is really simple, turnout great, registration automatic, etc... Things like A/B testing aren't needed, and most importantly, the voter knows the actual record of their vote contributes to the tally. Every voter gets all they need, and ample time to vote as well.
Unless we want personally identifiable votes, the system you describe cannot do that in a trustworthy way.
And having that trust in the record be true matters a whole lot more. This matter isn't bullshit. Having that basic trust in place is at the core of democracy. Participation does not require surrendering that trust either.
That is solved by actually educating people and not putting things in their way. The Oregon system does both those things. Outreach and education comes from parents and concerned others, until they come of age, at which point the State does this.
We don't need e voting. It's a solution in search of a problem.
Most of our systems are very corrupt and voter hostile. It is very tempting to apply technology to circumvent that. But, the truth is that same corruption will take advantage of the lack of trust and forced ambiguity inherent in electronic voting records that are not personally identifiable.
We have already seen this happen here in the US and other parts of the world. Voter trust in the actual record of their vote used for the tally is fundemental to trustworthy elections.