[Bigger is Better]

Yes go solid now. If you think aboout it the rear of the subframe connectors will be welded/bolted directly to the structure and if the front mount is attached to a subframe that moves you will eventually crack the welds. Anyways if you want to reduce flex with subframe connectors it goes hand and hand.

I like the ones from Dave at Pro-touring fbody and the ones from Global West.