Here's more detailed information on the successful Good Vagrant spawns.
For the first and second one I made appear (in post 26), I never went human. I started off dropping 2 separate bags of 1 Purging Stone at a time, then switched over to Repair Powder when I ran out. Nothing is dropped when a drift item bag is found, I suicide again.
Suicide # / # of Drift Item Bags Found (0 if blank)
1 through 24 - 0
25 - 1
26 - 1
27 -
28 -
29 -
30 - 1
31 -
32 -
33 - 1
34 -
35 -
36 -
37 -
38 -
39 - 1
40 -
41 -
42 - 1
43 -
44 -
45 -
46 - 1
47 -
48 -
49 - 2
50 -
51 - 1
52 - 1
53 - 1
54 - 1
55 -
56 - 1
57 -
58 - 1
59 - 1
60 - Good White Vagrant #1 appeared!
61 -
62 -
63 -
64 - (Switched to dropping repair powders here)
65 -
66 -
67 -
68 -
69 -
70 -
71 -
72 -
73 -
74 - 2
75 - Good White Vagrant #2 appeared!
The second one dropped a Transient Curse. I was stupid and actually missed the first one's drop, because using the Mega Mule I had 99 of most items and was maxed out. I walked away to drop 1 of every item to find out what the drop was, forgetting that I should've checked the bag after every handful of drops, because dropping a lot of stuff at once will cause the oldest-dropped bags to disappear. It disappeared on me.
Good White Vagrant #3 I didn't document in the same way. That time it was Sunlight Medals dropped, and then I switched over Purging Stones when I ran out. It probably showed up after around the ~70th suicide and dropped a Charcoal Pine Resin. I was level 125.
And now I just got another:
This one is actually of a previously-undocumented location, so it was kind of cool getting that done. It's listed in the Future Press Guidebook so I trusted one would appear in the area, but there haven't been any screenshots or videos of it that I've seen. It's in the Darkroot Garden, by the cliff where the group of Frog-Rays jump out of the water. It's in the far corner on the cliff-edge, behind the Stone Knight.
Level 122, same drop routine, this time starting with Purging Stones and then switching to Gold Pine Resin when I ran out.
1 through 31 - 0
32 - 1
33 -
34 -
35 -
36 -
37 -
38 -
39 -
40 -
41 -
42 -
43 -
44 -
45 - 1
46 -
47 -
48 -
49 -
50 - 1
51 -
52 - (switched to Gold Pine Resin)
53 - 1
54 -
55 -
56 - 1
57 - 1
58 -
59 -
60 - 1
61 - 1
62 -
63 - 1
64 -
65 - Good White Vagrant appeared.
The items I'm dropping are typically ones that the Good Vagrants are known to drop, asides from the Sunlight Medal, that was just a random choice. No idea if that's a requirement at all, but for now I'll be sticking with stuff like Purging Stones, Resins, Repair Powders, Transient Curses, etc.
I also had a failed attempt earlier due to my connection being lost and the game quitting to the menu, but I think the information might be useful still:
Level 450, Dropping 2 Sunlight Medals
1 through 33 - 0
34 - 1
35 -
36 -
37 -
38 - 1
39 -
40 -
41 -
42 - 2
43 -
44 -
45 -
46 -
47 -
48 -
49 - 1
50 - 1
51 -
52 - 1
53 - 1
54 -
55 - (switched to Gold Pine Resins)
56 -
57 - 3
58 -
59 - 1
60 - 1
61 -
62 -
63 -
64 -
65 -
66 - 1
67 - 1
68 -
69 -
70 - 1
There seems to be a reoccurring trend. It's a small sample size, but so far it appears that the stray bags start showing up most commonly around the 20th - 30th suicide attempt. The bags start becoming noticablly more frequent around the 50th suicide attempt, and then I've been able to find good vagrants around the ~65th suicide attempt.
Because I believe it relies on other players not collecting the bags I'm sending to their worlds, this is definitely not going to remain consistent... and I'm sure varying online activity will affect the viability of this (a PC player with connection issues may have less luck). However, having tried this in the Burg, Parish, and Darkroot Garden at completely different levels and getting similar results is very promising so far.
Again, I don't think the mechanic for spawning good vagrants has anything to do with dropping so many items in total, it's just that I'm basically spamming people with drift item bags over and over to the point where it's sort of 'overflowing' and they start coming back to me with greater frequency. ~65 drop/ suicide sessions may be a relatively common area to finally have one come back to you and turn into a vagrant, but I believe that is in NO way a guarantee.