I collimated one of those for my friend. I bought proper springs for primary mirror 'cos there were rubber washers instead and virtualy impossible to adjust. You can get springs for about $2.50 from Bunnings or Mitre 10. They come in pack of 2 and are long so you have to cut them in half and end up with one spare
The focuser have 1.5x Barlow built in and you have to take it out to be able to collimate it either with Laser or Cheshire or film canister. Mark the centre of the primary as you looks like already did and collimate it then. Make sure you put 1.5x Barlow back where it was otherwise you will not be able to focus unless you have tube extension.
cheers
bob