I think both of you have made good points.
I think that the 250k is slightly low and when people were exploiting the well relog bug to have as much time as the wanted 3 million valr was far to much. I think that 500k would be a much more reasonable number because even if you were to get 10 legacy cards you want to keep currently that is still 4 more well runs required to level those cards and at about 1 hour each attempt that is 4 hours of grinding not including the time it takes to get those cards. At 500k you are more likely to get a card or two that you want to keep and level it.
As far as spiders go, I helped with the 3 minute level and that was someone with the xp potion and stones, but spider power leveling was broken and I am glad to see that it was fixed. And I am hoping once parties is introduced in the coming weeks that the level requirement for dungeons is not considered so we can help friends power level. It will still take at least 20 minutes to level I believe, I could be wrong, and there seem to be some decent alternatives to spiders that is not running dungeons right now anyhow.