Which Metabones for tele-zoom? Testing 24-70mm on GH4

I’m selling my Lumix 35-100mm 2.8 as it does stabilise video but still shows signs of micro jitters when the lens is held quite still (v1.3). So I’m looking to adapt the Tamron 24-70mm 2.8 VC to use as a faster, longer zoom on the GH4. At the moment I only have a passive adapter (used in this video) but I’m thinking the Metabones smart adapter (non-speedbooster) might do the trick. Having 70 x 2.3 (c4k crop) = ~160mm @ 2.8 on the long end.