Another helpful reply thanks ...
What do you know? You're a DIYer who employed an SE to do his calcs not an SE!no 6x2 may well be fine you stated 4x2 in early post
8x2 may be to big and cost much more
the 6x2's would rest on the new 6x2 joists'.
The SE has been and had a look.
NO steel required.
Just waiting for his design now and then submitting through Council..
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