Does it start at Gold 6?
TIERS are different from MEDAL placements.
Tier is based on War Rating, during season, top down. And also determines what Map/Nodes your wars are on.
Medal placement is based on SCORE (points) during the season.
You could roughly estimate what Medal placement you will hit based on what TIER your wars are in (and thus what Points Multiplier you get), but not an exact science, and not a 1-to-1 correlation (you could calculate being within 1 Medal status away, but it's not like the cutoffs are exactly at the same places between the 2 different styles. And even then, Points will not line up exactly with everyone's WR.
You can tell EXACTLY what TIER each of your wars is, because the war matching, and the actual war joining (and points summary) screens for each war tell you exactly what your TIER is for each different war (and thus what Multiplier you have for that war). And Kabam is saying that the Radiance is PER WAR, so has nothing to do with Medal Standings.
Thank you