Hi - it's great to see the results of your questions an planning from the other threads materialise.
That's a great job there.
I am also a big fan of Osmo PolyX and have used it on 90% of my projects. To apply, I have used the white scotch-brite style pads. Scrub it in to the wood, use a cotton cloth to remove excess, wait for it to dry, and then repeat. Fast and fume free, and even I can't get it wrong (I don't do much finishing).
The original version leaves a slightly yellower finish, but I have tried a sample of the PolyX Oil Raw Effect (3044) for my coming baltic birch plywood project and it hardly changes the colour at all (leaving the birch a lot closer to the original white).
My supplier was able to send me some sample sachets of the different finishes to try out first.