This is the 50 block skywalk fort my team made in practice. It is a good example of a competitive fort imo. some key points:
- no 'entrance' is too long (disincentive to break walls)
- to cap the flag you must run right by spawn
- covered ammo/health area
- layers of walls to fall back on
- quick access outwards, slower going in
- many raised areas for rockeering :P

this place is a slaughtering ground for rockeer
I tried to make the same kind of fort in a public server and all the other team left
im sure the block limit on skywalk will be brought down if ever played in the league but the same concept can be used. also, we're still recruiting :wink: