Interesting question.
ICAO Annex 4 Ch 16 requires that WAC projections are Lambert Conformal Conic in separate band for each tier of charts. The standard parallels for each 4 degree band are 40 minutes from the north and south extremes of the tier. There is a recommendation in Ch 17 that half-mil charts do the same.
This suggests that the projection of an ICAO half-mil is likely to be on a single chart basis and, unlike the Jepp charts, you should not expect them to fit together.