So is anything over 250 soft limit not safe, or not over 500, or not over? Or has that not been determined yet?
The limitation is not related to block size, but rather number of transactions accessed/updated by a block.
In general, the default for 0.8 (250k) is fine. Raising that to 500k is likely just as fine.
But it is not very simple to answer the question, because this 0.7 BDB lock issue becomes more complicated with larger BDB transactions.
TY for the clarification.