the site says that moderators can validate too but idk if its possible since some parts of KoG are down atm and Qshar is doing some things manually atm.(edited)
playing solo is better if you want to fail less on maps, if u play team 0 your saving, reaction time, reflexes will get better. so if you think you need more practice to dont fail, play solo. if you feel like your saving sucks, play team 0.