Got back to this a bit late, but would agree with JD that any kind of multiple cut approach like that is asking to compound inconsistency. I use a ladder guide every cut just so I don't compound inconsistency. I did white oak about 9' long and 9/4 and did a lot of 28-32" slabs myself and they weren't that hard to slide off to one side and stack them. Granted, yours are going to be way heavier, but with a helper are easily stackable. Glad you figured out the minor washboarding was going too fast with skip, suspected that was most likely. There's the long held argument many CSM folks use that finish doesn't matter that much because it will have to be leveled again later, but again it's a matter of compounding inconsistency. People think that the leveling you do to take out any drying warp will take out all the washboarding at the same time. It won't necessarily. The warp and the washboarding may be compounded problems. Comes down to how much waste and extra work later one can tolerate. After doing about the same amount of work all over again as milling to router plane level a lot of my slabs, because I milled them somewhat poorly or didn't take enough care strapping and stacking and retightening the straps relentlessly, I've come to realize it saves me a ton of time in the long run to mill and dry everything as perfectly as I can.
If it's raw slabs for customers, you'll get way better money with a clean finish. If it's for yourself, you'll save a lot of work later on and waste less wood by making slabs as perfectly level and clean as you can to start with. I used to buy only skip chain when milling w the 880, wanting to get the milling done as fast as possible, but since milling primarily with lo pro I can use full comp up to 30" and get bandsaw like clean cuts and fast milling so I've lost interest in any form of skip til 30"+ slabs. Haven't ever gotten a shot at anything 40"+ so I only have theories so far on what will work best for that. Seems "double skip" may work well at that size, but yet to test any. From what I've heard from others tackling big oaks, it seems that the smoothness of full comp may offset any easier cutting that full skip gives, because if the full skip is oscillating it's taking out more of a kerf and doing more work and ultimately requiring the same amount of effort from the saw and you may not even be milling any faster. I also wonder if really fine chips from dense hardwoods are even that much of a factor as far as the clearing ability of a chain, compared to big softwood chips. Again, why it seems to me 3/8 or 3/8LP make much more sense in dense hardwoods, the chip clearing benefits of larger chain may be an non factor vs the enormously greater power that larger chain requires in dense hardwoods.
