Very good post all the info we wanted and looks like your off to a solid start as your doing your research.
I grow autos and I’m going to recommend not topping! Your Amnesia Haze is growing strong and the sativa in it is going to out grow your blueberry so you definitely want to keep that in mind now and make efforts to curb it so you can keep your canopy even in order to give your buds even light distribution so that your buds grow big and mature eventually.
Topping is a high stress method, this is not ideal for autos and their veg period is limited and you could stunt them as they don’t handle high stress well.
Because this strain is such a tall strain I would suggest you LST for sure but if you want the most out of you can do a FIM, it produces better results than a toping and is about the hightst stress method you want to use on an auto. It will give you 4 colas vs having 1 if you don’t or 2 if you top once.
It’s a well accepted best practice for lots of top auto growers, there is a great YouTube video here
Also try to shoot for 6.5 while on your veg growth and more of a 6.8 for flower.
I’m supprized your run off is so low being in FFOF but then again your a bit along and you didn’t fill your pot.
In the future here is so far the best method I have found to grow autos in soil.
Purchase ocean forest and happy frog fox farms soil, mix them each in their own bin until they are 30% perlite as cannabis likes airey soil.
Put a wine bottle or sometbing in the center and fill the pot 3/4 with ocean forest, then mix in Mykos (you’ll want to buy a bag of these they help your roots alot) only do this when your ready to pot not before in your bins. Pack it down and re fill it to 3/4.
Now pill the bottle and fill the remainder with happy frog and also mix in Mykos with the happy frog.
Soak the pot and then let it settle, top dress with some more soil So it’s full, overtime it will compact and break down.
Plant your seed or jiffy puck when started in the center.
The happy frog let’s your plant grow without risk of being nute stunted and allows the tap root to grow down deep fast, the Mykos will increase root growth and the perlite helps in many ways.
Again FIM your auto , if you don’t at least LST but you will look back and wish you Fim’d this is one of the best strains to as it’s strongly sativa and grows tall.
Here is my northern lights auto (strong indica) after fim
Ps. DO NOT CUT LEAFS OFF!
now if this plant ends up having weak auto genetics and doesn’t flip automatically then yes but otherwise leave it alone, Tuck a leaf Durring flower to expose pistils but for now just let it buck those sites don’t need light the leafs do