Lightning/summon witch build advice

So let me start off by saying the only time I've played PoE was during the open beta weekend a few months ago. Even then, it was only to maybe level 9 or so. I came up with this build after reading around some and looking at other builds.

I decided I want to play a lightning/summon witch when the OB starts, and here's what I have:
http://www.pathofexile.com/passive-skill-tree/AAAAAgMBVysHY3NTa9ttGcHzoqPDbX_GHNyTJ7-XyT3yHrQMRnGVIILH0_uofVqRKPrr7n0Y7Iq4k6cIj0bQ0JuhSOf318y8EJdEBIVgqsSdrhpspqyIQJAzLR-NGeAS3YzmTNlffq92EeTswbRqrM9lVcYWbxmFAuNJsiyc2QsqmPqAwFR5Awj0i3qnK-L3O-E=

I'm pretty dead set on staying a summoner. My reasoning for lightning was it sounded like it synergies well with pets because of the shock debuff. I'm not 100% sold on lightning. If someone thinks something else would be better, I'm open ears. I decided to cut off hard at 70 points, but if I decided to go higher I'm thinking probably more nearby life nodes and maybe Hex Master for conductivity and additional shock duration nodes.

Early levels, I'm thinking I want to get Minion Instability ASAP, so for my 17 point build:
http://www.pathofexile.com/passive-skill-tree/AAAAAgMBVysHY3NTa9sC40myLJyOvhEtfIPN-riTpwiPRtDQm6FI5w==

I was also considering getting MI even faster with 12 points:
http://www.pathofexile.com/passive-skill-tree/AAAAAgMBjr4RLXyDzfq4k6cIj0bQ0JuhSOffsJLB
But Lord of the Dead seems too good to pass up, although I would probably go straight for that afterwards, so it would be the same at level 19 as it would be at 17. I would have to use more respec points with this route as well. As such, I'm pretty sure I'll just be getting it at 17.

Build at 53 points:
http://www.pathofexile.com/passive-skill-tree/AAAAAgMBVysHY3NTa9sC40myLJy4k6cIj0bQ0JuhSOf318y8EJdEBIVgqsSdrhpspqyIQJAz2QsqmPqA6-4o-oLH0_uofVqRaqyVIEZxtAyTJ7-XyT3yHhzcf8aio8HzbRk74eL3pyuLegj0eQPAVA==

After that, I'm not sure if I want to go ahead and get my lightning damage nodes or get more life.

Any advice is appreciated!

Gonna say your build is identical to the one I was mapping out as well. I've had great success with Lightning and would say that after all minion items are selected to just go to where life/lightning damage is in the tree.

Are you going for casting lightning damage or using totems? I feel like using totems seems to be a better way to do the build since you can summon two totems, cast and trigger more shock

I was thinking probably cast and have a skeleton totem.