From looking at current availability for next July it seems they release 2 PE and 2 UC for flights. Thing is I'm after 3 in PE, assume only real option is to hold fire or book two PE and one EC and cross my fingers?
Correct as VS only initially release x2 Upper, x2 Premium and x8 Economy reward seats on every flight.
More may be released later unless you are Flying Club Gold where you can book any reward seat even if there’s none left by spending double the usual number of points.