The specs that I seen on the GC2400 were only 6.3 GPM NOT 6.9.
But either way I think it is going to be slower than you want.
If the 3PH splitter had a 4" x 24" cylinder with a 2" rod, It would take 12.4 seconds to extend and 9.3 to retract. Giving a total cycle time of 21.7 seconds. And with only 1920psi, you are only looking at 12 tons of force.
I don't think I would be happy with those specs.
There are a lot of good stand alone units like the huskee's from TSC, troybuilts i think at home depot, etc. Most of those are labeled as 22ton units and have the same 4" x 24" cylinder but with an 11GPM 2 stage pump. That would give cycle times of 7.1 to extend and 5.1 to retract. Total of about 12.4 seconds. And these splitters can be had for ~$1000, which isn't much more than a 3PH unit.
But If you must have a 3PH unit, I would go with one that has its own pump. But I think they are usually more expensive than the stand alones and dont even have their own motor to power them. I don't know of any good ones or what to look for in them either.