Primary universe vs general universe
A legislative candidate runs two campaigns with two electorates. Texas shows the gap in the Secretary of State's tables: the March 2024 Republican primary drew 12.94% of registered voters and the Democratic primary 5.47%, against 61.15% in the November 2024 general. Spread over an average Texas House district, that is roughly 16,000 Republican primary voters and 6,800 Democratic primary voters, and about 76,000 general-election voters. Your primary universe is a list you can knock; your general universe is a list you segment.
Build them as separate saved lists from vote history. Structured search filters on party, precinct, state house and senate district, and history; on the Campaign tier you can type it instead: 'Republicans in HD 28 who voted in two of the last three primaries' returns a saved list. The primary list is persuasion and turnout among reliable partisans. The general list splits into your base to turn out, the other side's base to skip, and the presidential-year-only voters in between whose history says they might show up.
Runoffs and the November after a contested primary are smaller electorates again, so keep the primary list intact after the primary; it is most of your runoff universe. Everything a walker or texter learns lands on the voter record as a campaign-scoped annotation, so the supporter identified in February is still tagged in October.