It doesn't look like the stain is taking very well. It's looking quite 'washed-out' at the moment to me, certainly compared to your original artist's impression. I've never used DT (and am unlikely to get the chance to) but the general feedback I've seen is that the surface needs to be rougher to absorb it. Normally 240 or 320 grit maximum. You may have over-smoothed it by going to 600. It's actually a nice finish as it stands, though the stripes aren't going to stand out as much as I think you intended.

It all depends on whether you want to improvise as you go along - or stick to your original plan. I'd be tempted to certainly give it another coat of the DT blue. I have no idea how much the intensifier coats will deepen the colour, though they certainly will to some extent.