Update March 4th: The main viewer download links on the Sunshine wiki page now all reference the updated viewer version (3.4.5.271118).
Update March 2nd: Just as a point of clarification, the update discussed here is not currently linked-to from the Sunshine wiki page. To obtain a version of the viewer with the updates, you will need to download version 3.4.5.271118 of the viewer (link repeated here for ease-of-refernce).
As I recently covered, a problem has emerged with Server-side Baking in that it “breaks” the Z-offset capability found in the majority of third-party viewers.
The Z-offset allows the vertical height of an avatar above the ground to be adjusted, such that sits and kneels don’t leave the avatar apparently floating in the air, and which allow those with very tall / giant avatars or very small / petite avatars and those wearing full body mesh to similarly adjust their vertical placement relative to the ground / floor.
The problem was reported to Nyx in week 8, and SUN-38 was subsequently raised by Henri Beauchamp on February 24th to officially log the matter.
On March 1st, Linden Lab issued an update to the Server-side Baking project viewer (release 3.4.5.271118) which is an attempt to address the issue.
The new capability is referred to as SH-3909 Support avatar height offset and is described as, “Adding a new visual param that allows users to manually adjust an offset for how far off the ground (+ or -) their avatar’s root bone is.Supports the +-2m range people are used to adjusting in their viewers, but new implementation should support server-generated appearances.”
It appears within the viewer as a new slider in the Body section of the Edit Shape floater, called “Hover”.

Moving the slider to the right or increasing the displayed value will move your avatar upwards, much as increasing the Z-offset value in a TPV will. Moving the slider to the left or decreasing the displayed value will move your avatar down. As with all the shape sliders, any changes must be saved prior to exiting the editor, in order to be persistent beyond editing.
The slider offers a huge range of height adjustment compared to the z-offset slider in the likes of Firestorm, and is somewhat less accurate – with most TPV Z-offset options, height above ground can be precisely adjusted to 2 decimal points, whereas the Edit Shape floater only allows whole numbers in the range 0-99.

The vertical range of movement can be considerable, and lead to some interesting results when saved – your avatar can currently disappear entirely underground, for example. Also, adjustment made using the slider are not apparent in viewers which do not have the SSB code – something which shouldn’t be a major problem, given the need for people to be using SSB-enabled viewers once the server-side code starting deploying to the main grid anyway.
What might be of greater concern, however, is the fact that the control has been incorporated into the Edit Shape options means that it cannot be used on No Modify shapes, which could leave those using such shapes still feeling aggrieved if they are impacted by the height offset problems resulting from SSB.

It’s an interesting approach to solving the problem – and it would appear that LL consider the matter now resolved, Nyx Linden having issued an e-mail to the opensource dev list which reads in part:
Added a new parameter to shapes to replace the viewer-side height offset. Since it is stored in a wearable, the new back-end can read and use the value. Will send an email to third-party devs later today to let them know to pick up the patch.
Marking SUN-38 as resolved.
Given that earlier in the week – at the Content Creation User Group meeting on Monday February 25th, where the subject of SUN-38 was raised, Nyx commented, “It hasn’t escaped our notice. We’re considering a couple different approaches … we’re considering a few different options. Suggestions appreciated, but we haven’t officially settled on an approach we’re going to commit to publicly just yet”, it will be interesting to see the response is to this particular fix.
With thanks to Latif Khalifa, who both provided me with news of the arrival of this update, and provided the necessary links for me to have a play.