Best inReach settings for Mountaineering?

In general, the more frequently you send points, the better the "track" on MapShare will look.

The Virdiana share appears to have benefited from syncing logged points as well as showing the iR sent points. That's why you see the relatively smooth, colored track lines (which result from sync'd logged points, possibly by way of activity syncing, not just iR log syncing). If you actually examine one of the track logs from the sidebar, you see the usual sent points connected by blue lines.

The 6D92W share suffers from the usual issue with heavily restricted sky view. In particular, the most recent track (right this minute) shows a N/S spider web pattern which is characteristic of a restricted sky view in the N/S direction. The climber appears to be on a very steep slope with a high ridge to the south. The resulting spider web is a combination of restricted sky view (cannot see satellites lower in the sky to the south) and possibly multi-path reflections off of the face. No matter how often you send points, you cannot compensate for the fact that the fix is lousy.

The PakTeam share suffers from some of the same issues, but in an E/W direction, near the center of the track.

Bottom line here: More frequent sending is better. But nothing will compensate for the challenging GPS reception conditions which are inherent in mountaineering.

Thanks very much!

With what you said in mind, I looked more closely at the recent tracks of Virdiana and Fiamoncini (6D92W).  Your explanation of the restricted sky view makes a lot of sense.  What puzzles me is that Virdiana and 6D92W are basically in the same position, climbing the same route; you can see this if you zoom in and the mountain features appear.  I clicked on some of the track points of Virdiana, and it seems like most of hers update every 30 minutes (sometimes it is off, probably because of the difficulty in GPS reception that you mentioned), although sometimes it seems more frequent.  Looking at Fiamoncini it seems his is set to update every 10 minutes.  I'm wondering if some of the difference may be due to where they are carrying their device (tucked inside a pack or pocket, etc.).  

I do need to think more about the difference between log points and sent points.  I thought log points wouldn't be sent to Mapshare via satellite, and would only appear later once the inReach was synced to a computer, but I am pretty confused about this.  I don't know how Virdiana is sending log points to Mapshare where she is.   A couple of months ago that was confusing me when I was testing my device on walks in my neighborhood.  Thanks for bringing that to my attention; I need to figure this out.

I did notice that the two clusters of spider-tracks were in approximately the same position. Without any concrete information, I wrote off the variation in spider orientation to either (a) differences in the satellite constellation (assuming the parties were there at different times of day), or (b) small variations in actual position which might "shade" different parts of the sky because of the extreme terrain, or (c) difference in the type of unit or where the unit was carried. 

Where/how the unit is carried is a good point. For example, if one party is carrying the unit on their left hip and the other is carrying it on the right hip, the body shades a completely different portion of the sky.

Although it may not be practical for mountaineers, the ideal position for any iR device is high on a shoulder strap. This limits body shading to the head, which is a much smaller object.

You are correct about logged points. They do not show up on the MapShare maps (or anywhere else) until sync-d. They simply remain on the device until then. Also, activities are a different beast, sync-d through a different part of the Garmin ecosystem (the Garmin Connect part as opposed to the Explore part). The smooth colored lines really ARE activity lines, not iR lines. You can tell because the Viridiana MapShare sidebar HAS activities. And if you hide them, the smooth colored lines disappear.

One way or another, those did get sync-d. Sat phone? Connection at a base camp somewhere? No real idea how, but they did get sync-d.