I got the 230-4 and it splits everything I want it to (I split about the same amount you will). Mine has the 4-way knife capability which I use all the time. It pretty much splits wood twice as fast that way, besides being able to split both directions. I think it added a bit to the price though as did the lifter (which I also am very pleased with). I don't remember the pricing, so call Split-fire or ask your dealer for the $ breakout. Pricing may have changed since I got mine anyway (I got mine 1.5 years ago). I got mine directly from Split-fire since there were no dealers in my area. I also told them to make the 3ph mount i-match (quick hitch) compatible. That was about $20 more and well worth it to me. They can also paint it any color you want for a little more $ or use a tougher epoxy paint too.
I might add that I run my tractor at about 1500 rpm when using this splitter. That's plenty fast for me with this two way splitter, might be a little slow at that speed with a one way splitter using the same size hydraulics.