...I would like to keep the weight of the subs right down to around 20kg per box
...Yamaha DXR8 or DXR10 mk2 tops over one of the above subs.
...What would you recommend?
Do you always use, or need, a L-R setup? Here is another option.
This has been my go-to pub rig for about a year. 1 DXR12 over 3 ZxA1-Subs. Very small, physically stable, clean, has even dispersion, and get incredibly loud. Easy transport and setup. One has to experience this. It is overwhelming when you want it to be. It is scalable.
Set DXR D-Contour to Off, with HPF120Hz. When paired with DXR10 or 12, set the ZxA1-Subs to
Invert Reverse Polarity. The Subs are Aux fed.
My opinions: The 10s are really great for the vocal range, but are a bit "dull" in the highs (in a pleasant way). They sound good but will not get very loud.
When the joint is jumpin' at the end of the night, you will wish you had the 12s. They have a much fuller sound with extended highs and significantly more output. The 12s are easy to handle and they rock!
I use a DXR10 or a Zxa1 on a tripod as extensions in wide or odd-shaped rooms where I need coverage "over there" (typically at a lower level).
-Dennis