Good stuff and thank you. I apologize as I saw this posted before but I have an issue when I'm auditioning new sounds that I've already established a split for, the new sound will erase the split points and cover the entire range which results in me having to re-establish the split points each time. Is there a way that you can audition sounds and retain the split details?

Unfortunately, I do not think there's a "Param. with PART" setting to retain split points of the original PART getting replaced.

Not 100% regarding your question - but a reasonable summary of the 3 "Param. with PART" options:
https://www.yamahasynth.com/ask-a-question/is-there-not-a-param-with-part-on-off-option-in-montage-can-it-be-added-with-next-update

Good stuff and thank you. I apologize as I saw this posted before but I have an issue when I'm auditioning new sounds that I've already established a split for, the new sound will erase the split points and cover the entire range which results in me having to re-establish the split points each time. Is there a way that you can audition sounds and retain the split details?

Yes, there is.

When you are constructing your Performance, and you are using multiple Parts to create a Split... you can maintain the designated Split point while auditioning new Parts. Here’s how:

Let’s place “S700 for Montage” in Part 1
And place “Upright Bass” in Part 2
Create the split as follows...
Set the “S700 for Montage” to play C3 and above
While the “Upright Bass” is set to play up to B2

Say you want to try out new basses.
Press [PART SELECT 2]
Press [SHIFT] + [CATEGORY SEARCH] to launch the ”Part2 - Category Search” screen

Along the bottom of the screen, find the “Param with Part” option boxes — you will want opt out on “Mixing” — turn this box grey... by doing so you will not bring along the mixing settings from the Bass Part you are substituting, it will maintain the split point and other settings that you have setup on your current Mixing.

Unfortunately, I do not think there's a "Param. with PART" setting to retain split points of the original PART getting replaced.

@J, fortunately there is...
“Parameter with Part” — When the option is green, it means that the Part you substitute will come in across all keys, and at the volume, in the Pan position, with the Effect send amounts, etc., etc., etc., as set wherever you are recalling it from... but if you turn the “Mixing” box grey, your current settings for all of these parameters will be respected.

... wish the Reference Manual would be updated sometime to fold in the supplementary manual information. But my mistake for not reviewing the supplementary first before responding.

ok and Thank You again (now bookmarked 😀 ) I would think it may be a benefit in a future OS Update to segment the "split-layer" settings from the rest of the "Mixing" settings as a separate checkbox. Ideally I'd like to audition the sound as it was intended to be heard. The key-split range really should have no impact to that.