If you are looking for strong but reasonably light I would consider loosing 4 more spokes from the front instead of the back (meaning 32r/24f or 28r/20f). In the front, all spokes are doing the same 'work' so 20-24 should be good. But most spoke failures occur in the rear where each side of the wheel has a different job and are at different tensions and the rear is supporting more weight than the front.