Soilless advice needed please

If i'm using ProMix Bx can I use full strength nutes or is it still recommended to go 1/2 strength

Id go 1/2 strength then respond to your genetics. It seems like the bx is very similar to most other soilless mixes and should be able to handle heavier feeding than most soil mixes.

Is this from week one or should I wait a week before I start using nutes?

Seeds in week 1 most likely need no food. Rooted cuts usually need 1/4 strength during week 1. For transplants id say 1/2 strength is a good starting point

Thanks fella