How to install James Hardy Secura flooring?

[Neen]

I am installing a laundry in an enclosed veranda of my 66yrs old home. 

My home is on stumps. I have removed 19mn  jarrah flooring as to allow me to install James Hardy 19mm Secura Interior Flooring. 
my question is as my joists are old very hard jarrah can you advise what to use instead of using a nail gun with 50 x 2.87 round headed nails. I did a test run and using a Ryobi nail gun the nails protrude 2cm above Secura sheeting. I

can hire a Paslode nail gun which may have a little more oomph but I’m sure it will do the same as have had difficulty in the past nailing into jarrah stud walls. 
Can I use clouts or screws?

[MitchellMc]

Hi @Neen,

You can use 8G x 40mm timber screws instead of nails. I can't see you being able to drive clouts in if the joists are that hard. Here's the Secura installation guide.

Hopefully, the screws will drive into the Jarrah, but if not, you might need to pre-drill it to allow them to penetrate.

Please let me know if you have any questions.

Mitchell