This is very similar to y_svar, but for per-player data so requires y_users:
#define MODE_NAME "Mode_Test_1"
#include <YSI\y_users>
#include <YSI\y_uvar>
enum E_PLAYER_DATA
{
E_PLAYER_DATA_SKIN,
Float:E_PLAYER_DATA_HEALTH
}
uvar gPlayerData[MAX_PLAYERS][E_PLAYER_DATA];