Dear FT RTW experts: I’m planning a DONE4 RTW and am very out of practice (I did several a decade ago…).. Could you please let me know any obvious errors in my approach?

- origin OSL (I need to go there later this year and it also seems well priced for DONE4, cheaper than LHR, HEL, CPH)
- D rather than A because first class isn’t on enough legs to make this worthwhile
- rough routing OSL-Seoul-Perth-SYD-BNE-SFO-New Orleans-BOS-LHR; later LHR-OSL
- used the “beta” oneworld planning tool, a bit weird the way it messes with dates but it claims to have found valid availability
- SYD to US is problematic but I think I can find D class by going via SYD and/or LAX
- checking with expertflyer for D class availability and adjusting dates accordingly
- then I will call Finnair in Norway to book over the phone — I can apparently send the routing from the planning tool but it is refusing to let me choose some flights that I know have lots of availability (eg SYD-BNE open all day but it only lets me have 0600).

Are there are any new quirks - or new tools - since I last did this? I’ve had a read through the stickies in the forum but there are so many now…!
On those routes are there any catches I should look out for (eg particularly crap aircraft I should avoid)?

Trip will be in April and May. Goal of the trip is to visit places not to build up miles or status.

Thanks for any pointers.