My experience training Synethsia as a Synesthete

[red book]

Hey, 

I've been passively training Synthesia for about 2 weeks now with the use of this google extension: 

https://chrome.google.com/webstore/detail/synesthetize/ldljgghnflfphlnpneghciodeehilana. 

I can say that the new associations I have made are not quite the same as the deep associations I already have. For example, the number '4' is inherently coloured indigo for me, and the essence of indigo seems to contain with in it the number '4'. While through my training I have new associations such as the letter 'S' being turquoise, this association however seems to be of a different kind. I see 'S' as turquoise, but the connection feels reversed, almost as if 'S' is primary and its colour secondary. I would be interested in hearing non Synaesthetes experience with this kind of training. What feels primary, the colour or the symbol?