Well, IMO its already good enough. It all depends of the mob...some monsters, like efts, might give you time to even use simian trash after these 2.

You might be able to use them both even at faster monsters...but this will all depending not of connection, but accuracy. Jarring strike will always give you a 1~2 seconds window from stun when it lands, which is enough to prevent mob from attacking before you use haymaker. At slower mobs you can do exactly the same, but putting haymaker first and jarring second so you can follow with simian trash.

However, i believe that, depending of how auto-attack is implemented, the window may become more constant for both small and bigger mobs, which will help using macros like this.