I am pretty sure i'm beating the dead horse on bringing this one up again so for that, I apologize. I know everyone who has played had to end up frustrated because of ditches that should have counted as successful landings (those who actually care about landing anyway)
Just some suggestions here
1. The ''safe'' bubble extends D200 of concrete
2. Within the base borderlines
3. If not D200, then at least half the size of the concrete one is trying to land on. For example, runway isn't very wide across so the 'bubble' should be the size of the larger pads