For me I would start with Canna flower and a smalller amount of Canna veg then your bloom feed,,,maybe some cal-mag if your running LEDs ,,, ,,I flushed with pure rain water and the runoff was 1.4 EC which is a way too much for this variety, so @Creeperpark was right again. I continued to flush till 0.7 EC and will start feeding again with 0.7 EC with my next watering. I have Canna Terra Flores, CalMag, and PK 13/14, which nutes you would recommend to use after the flush?
build it up if needed and your come to a sweet spot with your plants,,,
plants will tell you what ya need and what you don’t ,,
I go with 10ml per 10 litre of water with Bio Veg all the way through until flush at week7 on a 10 weeker and just Bio Bloom and Top Max once the flowers start forming ,,,,
all the very best ,,
keep a bit warmer and as you mentioned it’s all great experience in learning your skills ,,,,,
I'm nearly 60yr old but you never stop learning even after 25 years for me,,,
peace and regards,,,,