Reclaimed parquet gaps

[sparrowfox]

Hi all,
having some reclaimed parquet laid and just wondering how to fill some of the gaps before sanding. I've got a thin wax to finish it.
was planning on using pva and sawdust but read that's a terrible idea. Is resin and sawdust okay? ...and what kinda resin do I buy? Thanks for any suggestions

 

[Tigercubrider]

Isn’t the layer doing the filling?

Granted, when my floor was sanded, it was laid already.
There was a small DIY repair where I filled in the damage from original French doors being converted years before to a patio door.
The refinishing guy sanded several grades and did mix the dust with a bonding agent. Quite likely an Osmo product from memory.