I have tried used the 600 Hortilux for both veg/flower with ok, not great results...I just bought a Conversion bulb for my sytem off ebay...its a Metal Halide conversion bulb from GrowBright that works on my HPS ballast

The blue/violet spectral range for Hortilux is about 9% of overall output
while the conversion bulb is around 50%
The red/orange range for Hortilux is about 80% and the conversion bulb is almost 50%

In my opinion...The hortilux really isnt designed to do both veg/flower