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Broke my chain this morning and had to remove a couple of links to fix it. This is with all the air out of the shock.
What sort of angle should the rear mech be at on big sprocket , full compression? Not that I’ve ever bottomed it out.
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Can the mech arm move at all?
It moves a bit.
I’ve done full compression and added 2 links to the large sprocket but that’s far too long on small cog.
Is that definitely the stretchiest location? It's not always longest with the shock bottomed out. And with some bikes you want to allow a little extra for flex, too...
I'd say that's too short, personally. And being a Zee it won't like it one bit if it is- they're a mix of SLX and Saint parts so if you stress the mech, the Saint parts ignore it and the SLX parts scream in pain. But can you win any back with the b-screw?
The picture is of the shortened chain. So I guess as long as it’s a couple of links longer than the picture I’ll be ok.
If you’ve got the shock compressed already, assuming you’ve got a removable link rather than Shimano pin style chain, why not just do chain sizing properly?
Take the chain off, cycle the back end through its travel until you’re sure where the point is that the distance between axle and crank is furthest (very unlikely to be at full) and tie the back end to the seat tube with string or something. Then put the chain on the big cog and the chain ring (this would be biggest ring if more than one) but not through the mech. Try and match the ends up - you should be looking for the ends touching plus enough extra for a full pair of links (so about an inch). If you have less than this you can see how short your chain is by now and decide if you’d rather replace ... :/ Once you have the length then thread it through the mech, rejoin it and stick the air back in.
From the pic I reckon you may be a bit on the short side, but without seeing it at the full length point it’s hard to say.
Obviously, as the full length point in the travel isn’t (usually) at full compression, the pics supplied aren’t really helpful for judging length...
Agh. Northwind beat me 
I'd be putting a new (longer) chain on. I don't think I'd be very happy with it like that.
Vince, I have already done that and as I said the chain is too slack when in the 11 tooth.
I haven’t actually mentioned that I’m fitting a new chain .
I reckon I'd put one more pair in it.
The Zee mech is really pretty marginal for 1x, the short cage means it can't cope with some suspension designs- it has enough "lever" to take up the slack on the cassette itself but a stretchy bike can need more. So you've got way less margin for error than with a medium cage.
^ +1. Shorty cages are great for rock dodging, but they just don’t have the capacity for a very big cassette. 1x11 is really pretty close to their total capacity just on the chain needed to cover both ends of the cassette.
It all came off my Fatty and worked fine on that.
Putting it on my 5 has been a monumental pain in the arse all the way.
Might put my 9 speed back on and get a 30 tooth front .