If I'm looking at a pumpstack taller than say 30 or 40 levels, I usually opt for a dwarven-powered minecart magma collector.
Basically, it works very similar to the design posted here:
http://dwarffortresswiki.org/index.php/DF2014:Magma#Design_2The primary difference in my setup is the way I collect the magma.
The magma dumps into a 1x1x2 chamber with a pressure plate in the bottom set to 7/7 magma. Once the chamber reaches 7/7, the switch opens an adjacent fire-safe door that drains the magma downward into an arbitrarily deep 3x1 chamber.
This chamber is hooked to a small inactive pump-stack with a disengaged gear assembly. Near the top of the chamber is a another pressure plate with 7/7 magma. This is set to engage the gear assembly. When the pressure plate fires, the pump stack is activated for 149 turns and pumps into a chamber sized* to prevent evaporation when emptying the 3x1 stack.
Just set it up and it'll run until the chamber is full. It's a good idea to create some kind of feedback that will stop the system if it reaches capacity. A secondary 7/7 pressure plate above the pump-stack activation plate set to disable the rollers out of pile C works good for that.
When set up, it's fully automated and can be used to slowly collect an arbitrarily large pool of magma for use around the fortress.