I don't know if luck modifiers affect the shards, though there is supposed to be a "bad luck mitigation" that improves your odds as you continue the activity.
It seems to measure according to each action, not to the amount of xp gained with the action. So even an action with minimal xp will count. I've heard people say that activities with higher xp (or more "active" vs AFK) are faster, but I can't confirm that. Didn't seem to make any difference when I tried it.
The average time for a skilling shard seems to be 3-6 hours of the activity. For example, you can expect to spend between 3 and 6 hours mining for the gathering shard. Maybe less if you get lucky.
I can't speak to the time/odds from normal combat since I used the strength platform at the beach to get my combat shard. For the boss shard, I joined in killing the KBD, which took around 320 kills (give or take), which seemed to be the going rate.
Yes, if your inventory is full, it will go to the bank. If both are full, I think it can be collected from the Wise Old Man.
20-Jun-2023 16:48:28