BTW: While Israel pointed the finger at Assad for the gas attack, that doesn’t mean that that is true!
Geller points out that the Jihadist opposition to Assad had already been in possession of Sarin. http://www.freerepublic.com/focus/f-news/3062613/posts
I am a strong supporter of Israel, but I wouldn’t be surprised if they “manufacture” intelligence to their own advantage.
Israel never blamed Assad using chemical weapons. Some experts or individual ministers may did so but it wasn’t official position of the Israeli government. Regarding your last statement, manufactured intelligence, IMHO Israel have more to lose if Assad removed from power and Syria descends into chaos.