I think the safe standing thing is a great idea myself -would get the matchgoing experience back to more what it was like when I was a regular.
But, and its a big but, the one proviso is that groups of mates have to be able to stand together. Otherwise, most of the atmosphere benefit of a standing crowd would be lost. You're still just as likely to be a miserable git if you are at the game on your own irrespective of whether you are standing or sitting. But with a big gang of like minded mates, well that's a whole different dynamic.
I'd prefer making any safe standing area an unreserved stand [although you'd still have to buy your tickets in advance, like now]. Then, just like the old Kop, if you want a good spec, you get there early. This helps build the atmosphere before a game too.
Alternatively, if the club wanted to keep the reserved seat structure, it could still be done through the membership scheme.
For instance, I'm a memeber at Lancs cricket club, and seating for members is generally unreserved. However, for test matches it isnt, but whenever you buy test match tickets via the Lancs membership portal, they always ask you if you want to sit by another member [or members]. It works great.
I realise its a whole different scale in footy, but it would be dead easy to have membership software with a 'preferences' page, which you could update with your mates details so you were all kept together.
Just a thought like.