Little bit of progress, started the repairs on the cowl area, and coated it in a product called KBS rust seal. Very similar to POR15 and it has worked great so far for me.
It's a 3 part system, 1. Aqua Kleen ( Degreaser ) 2. Rust Blast ( Converter ) 3. Rust seal (sealer / top coat )
The Rust blast worked very well on what I would consider heavy rust, however it took a couple of hours of constant spraying and wire brushing and I used almost an entire bottle on just the side inner cowl area that is in the pictures above.
Regardless it worked great and the Sealer looks really nice and levels out nicely.
Also started striping the floor back to bare metal and coating with the KBS system. Didn't bother with the rust blast as it was completely bare metal, just the cleaner and sealer. Came out great and hopefully wont have to touch it ever again. Have left some areas un touched as they will be cut out when the floor pan tubs and firewall are replaced.
Little comparison, before during and after.
Bit more progress, done as much of the floor as i can, also painted the underside of the dash, parcel shelf and rear firewall in a semi gloss black. Will all be covered in dynamat anyway but a layer of nice clean smooth paint doesn't go astray.
Also used sikaflex 227 to seal up all of the panel seams, messy stuff! Didn't turn out too bad, i just need to go around with a razor blade and cut off any stringy bits.
Rust repairs will be finished this weekend hopefully, and i might take a saw tot he firewall as well if i have time, that will be a nerve racking experience haha!