very little choice leh, my desk smalll and my screen is 34" ultra wide.Once upon a time, I put my speakers above the monitor. Actually many studios do that too... but they do have an angling mount to point the speakers downwards.
But yea, tweeter behind the screen is generally a no-no. How do you even get your speakers to fit behind the screen to begin with. Some speakers are short (e.g. Audioengine A5+) but that's still 23cm
But to get the Pebble as a consequent is... mmmmmmphffff. I mean, it is ok for what it is, but it might be better to see what your table can fit before choosing the last resort. I would pick iLoud over Pebble any time, but we're talking about a $40 speaker... so it works
so i can only put slightly behind monitor screen and if the speaker/monitor height too high, it will be partially block by the monitor screen. my table to monitor screen bottom is only like 12cm+ depend on how i adjust it