It sounds like you’re mixing tax liabilities and residence and more specifically primary residence of which the state has no control of its definition. Primary residence is specifically what we are talking about here as that defines voting in federal elections (some cities and states allow for non-primary residences to vote in local elections), D.L., CCW, and anything federal like a 4473.
Within the realm of the California State CCW statutes which authorize local authorities to issue CCWs, the State very well does have the ability to determine what "residence" means in regards to issuance. However, it hasn't.
The state statutes have a number of definitions of residence, including the Vehicle Code and Election Code and Probate Code. But, the CCW statutes don't have a definition. However, in 2014, there was a court case regarding the definition of residence/resident specifically as it pertains to CA CCW issuance. That was
Sigitas Raulinaitis v. Ventura County Sheriff's Department.
{It's a long document, but contains a wealth of information on domicile v. residence, legislative history and case law applications. Analysis of domicile v. residence begins on Page 20, line 8}.
Briefly, Raulinaitis was a realtor in Southern California who couldn't get cleared for a CCW in Los Angeles County. So, he bought a condo in Ventura county and claimed residence there. He registered his cars and registered to vote in Ventura County. In processing the application, the VCSO determined that he was actually living in another county and his son was staying in the condo. He was, therefore, not a resident of Ventura County as it was not his "domicile". The court went through a lengthy analysis of domicile v. resident and supported the VCSO decision.
Citing
Smith v. Smith (a divorce case) the Court noted
Courts and legal writers usually distinguish “domicile” and “residence,” so that “domicile” is the one location with which for legal purposes a person is considered to have the most settled and permanent connection, the place where he intends to remain and to which, whenever he is absent, he has the intention of returning, but which the law may also assign to him constructively; whereas “residence” connotes any factual place of abode of some permanency, more than a mere temporary sojourn. “Domicile” normally is the more comprehensive term, in that it includes both the act of residence and an intention to remain; a person may have only one domicile at a given time, but he may have more than one physical residence separate from his domicile, and at the same time.
In that case, the 9th Circuit Court of Appeals
affirmed the lower court decision, saying:
...the evidence showed that the Ventura County Sheriff's Department interpreted the residence requirement in California Penal Code section 26150(a)(3) reasonably, investigated Raulinaitis's residence thoroughly, and drew reasonable conclusions about where Raulinaitis resided.
So, voter registration and auto registration aren't be-all, end-all factors. The concept of "residence" and "resident" appears to not be merely the act of establishing a location to live but also the intent to use that location as a place they intend to remain. 51%/49% use time evaluations weren't used in the discussion.
Enjoy.