Hi all - I've returned to Pianoteq having tried the demo for a few weeks then purchased standard on release of version 8. I used to have an old version 6 but ditched it... but 8 has bought me back

What do you mean "ditched it"? If you still have the license and have not sold to anybody, you qualify for an update, which is much, much cheaper than a new license. So you can then use the saved money to buy many more pianos and somewhat resolve (or at least mitigate) the dilemma about what to pick.

Any thoughts on the Fiio K3? I'm now wondering if i ditch it and save the hassle of trying to work out what is up. Will the sound be improved with it? - I'm guessing it'll be marginal possibly? Does make music sound recordings sound better to me though.

Funny thing is I hated the Hamburg D on v7, but I'm loving it on v8. Strange, I wonder if they did such a big revoicing or I'm having placebo effect.

I doubt it, the D models have both been improved.

Technically you'll have to choose all of the piano at once.
However you have  a 14 days allowance of buyers regret. So if you decided you'd picked the wrong pianos you can contact them around the endpoint and get them to swap some of them.
KIViR free instrument package is also excellent. 

The D pack is a total no brainer. Not only is the Steinway D the completely undisputed king of the concert hall (nothing even remotely comes close) you now get both the American and the German versions in the same package.

Funny thing is I hated the Hamburg D on v7, but I'm loving it on v8. Strange, I wonder if they did such a big revoicing or I'm having placebo effect.

The D pack is a total no brainer. Not only is the Steinway D the completely undisputed king of the concert hall (nothing even remotely comes close) you now get both the American and the German versions in the same package.

I have two questions and am really grateful for any help - I'm not really technical so grateful for simple comments to help me...

1). Do i need to choose all 3 pianos on activation? - or can I choose one now and think on the rest for example?

2). I have a Kawai CA67, new HP Pavilion Ryzen 5 with Senheiser HD598's. I have a Fiio K3 Amp which I've tried using on the trial version (using Asio) with no luck. Without Pianoteq the Amp works but when on Pianoteq the laptop recognises the K3 (it's listed in the menu when selecting audio) but no sound produced. Swithing to headphone jack without using Amp works with pianoteq at this time though. Any ideas - am i missing an option somewhere or is it not possible to run the Amp through USB while on pianoteq with Asio?

Thanks...