Yes they were visible when attached at the hairline. I notice them of course since I'm looking at everything in minute detail and scrutinising everything to get it as perfect as possible- my goal.

My first order was a stock piece, so I'm not sure if knots are bleached on those since I didn't request it. I think John commented before that the darker the hair colour, the harder it is to bleach.... Since bleaching too long damages the integrity of the knot itself. So it seems to be a trade off with bleaching the darker colours- shorter bleaching, with some knot visibility versus longer bleaching, causing damage to the knots.

Bleaching the darkest colours seems to be difficult so I'm just going to order a blonde colour which has no knot visibility and dye the hair dark myself- it's all a learning curve for me and if this is the best way to guarantee invisible knots I have no issue with taking this extra step.

Perhaps ordering a blonde front and dying it yourself is the best way to go on this for you. Lets see what others recommend.