SpeedTree for mobile - experiences? overdraw?

I’m looking for a solution for having +/- 20 nice looking realistic trees for an archviz project on the Oculus GO. Already tried: SimpleSummerTrees, LowpolyForest, RealisticTrees, NaturePackage.
Problem is: they all have a very high overdraw - large fps drops (about 40 fps less) - several 1000’s of polys (and using lods) per tree is not the main problem.

Any experiences by people on Speedtree & Oculus GO / mobile? Is there a (mobile) pack that performs well and doesn’t suffer from (too much) overdraw?