Base Camp at 4300 is fine, but you need to get up very early to reach the summit. You can also camp at waht is called Moraine Camp. At about 4800m , this will save some 2h00 of sleep. When we where there, a bunch of people, including a Peruvian guide, got their stuff stolen (sleeping bags, boots, etc). I recommend hiding you stuff before going up.
Only map available of 1997 (2ÂȘed): IGN of PerĂș, Huari, serie J631, Sheet 1452 (19-i). 1:100.000. This map don't had the names of the main mountains, but the lines of level are O.K. (Vallunaraju or Ishinca don't appear with name in the map)