Advantage by Type of Blackjack Hand

I've been experimenting with topology maps in an attempt to better show statistics by type of Blackjack hands. The attached Advantage Surface Chart shows advantage for the various first two cards. X-axis is type of hand (all hard hands, soft hands and pairs). Z-axis is dealer up card. Y-axis is eventual advantage given six deck, Wong's Hi-Lo strategy, 1-8 betting spread.