I personally think that you should not say 'building towards' the big cat combo. If you have Saheeli Ray and
Felidar Guardian then six land in your first hand you should keep it.... EVERY TIME. Unless your playing control, there is a very slim chance your opponent will have an instant speed answer by turn four. I would however be cautious because if you go up against an aggro deck solely designed to aggro out combos, you will probably be put on a life clock and you will have some close magic.