If they're going to do it (I'm not ITK, it's just a hope from me) then yes, I can't really see them not doing both at the same time which complicates things.
The roof support from the steelworks inside of the spirals supports the front edge of the stand. The back will be on steelwork that goes down vertical I think. There's no reason I can see to stop them doing what they did with the South stand and put new vertical steelwork either along the centre point of the spirals to support the back of the new stand and having the new exterior only half enveloping the spirals, or just make it bigger and enveloping the spirals entirely. The steelwork could still be used for the cable supporting the front lip of the roof.
I'm envisioning the exterior lip of the South stand sweeping round to make it a bowl shape again. There still looks to be enough space with the existing E & W steelwork leaning back for a lot of leeway.
It won't just be a 'few rows' either as the seats can be extended sideways to more or less meet up with the N & S tiers (I can't recall what figures were being bandied about). There'll be all the extra concourse space for additional corporate and fan food & drink outlets as well.
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