[3.5] Winter Orb elementalist league starter, SSF/beginner-friendly

Hello, I'm trying to follow this build but I runned in some mana issues.
I'm level 88, the tree is almost complete as described in PoB but I don't seem to have enough mana to sustain Winter Orb's charges.

Killing packs works great because of mana on kill but on single targets I can't even get the charges above 8.

Am I missing something ? How can I best address this issue ? Straight up +mana, +mana regen, anything else ?

I've tried changing some items to gain more mana/mana regen (current build below) .. it's better but long way from enough, especially when I spam Whirling Blades during a fight.

Any ideas greatly appreciated.

HI i'm a total no0b, I see this is 3.5 and not 3.6 (i'm guessing this is a patch old) Is this guide still viable and cheep? I looked at a bunch of videos and this one had, I think, the coolest looking skills.
I made a character a few years ago with out looking at any guides and it was.... rough (I was also an idiot trying to stack shields). I"m not looking for super op, just viable and cool looking.