I had pretty much retired from raiding before I started to solo as I had previously always 2 boxed and so my gear isnt exactly how id like it but ...
I have had good success with a solo spec and have enjoyed tanking as a warlock.
I did respec for soloing and this made a huge differance to what I can kill and how fast I kill it. In particular I now only bother to root tough names , everything else i simply toe to toe and I mellee.
The magi shielding line with rougly 1k extra mitigation and the awesome shield itself make toe to toe very viable.
First I do run propagations and I do not remove proc gear , frankly I want my heal and power procs of which I have roughly 3-4 of each to go off as often as possible.
heal proccing items really do add up and I get a surprisingly good heal parse when toe to toe.
Most of the best solo items have been named nest robe, oob ring , vultak eye , misty protector , orb of necromancer but dont forget power on tougher names this becomes an issue so I use mmc power proc robe , vaults hat and I nice one for your collection is the T'hoth (sp?) bracer with arcane stun 5 on it.
To be honest I didnt know of the dagger with a stifle on it and maybe ill look in to that
Part of my thinking on this spec is I will probably mostly solo the next 10 lvls and I want to be as strong as possible to do so. (itll be fun trying to solo the likes of nizarra and stuff too with an extra few lvls.)