As the OP asked about the Matrix and Lombard Street it sounds like he'll be riding the original red, rather than the (IMHO superb) Pie Run/Mushroom Pie shortcut.
I can't say that I've every experienced condition-related difficulties on the Matrix or Lombard Street. They don't have enough rock or roots for traction problems. Magic Mushroom can be a bit slippier in the wet but there's been work on it this year so it doesn't collect puddles like it used to.
I usually do either Pie Run/Mushroom Pie, Matrix/Lombard Street or Double X/Black Dog rather than doubling back and doing more of them. On the other hand, it's an incredibly short ride to the start of Mushroom Pie from the start of Magic Mushroom so usually that will get done irrespective of the route choice. 🙂
househusband, while I too liked the challenge of "That Bit" (it's official name!) on the Pie Run, it was getting to the point where it was killing the flow of the section for most riders, especially those riding it sight unseen. I think it was a good call to get the 'fairies to smooth it out a bit. If only we'd managed to sort out the "Trail Perfection" switchback to the same standard, instead of just adding rocks to its roots…