I've been using my sons old affinity carbine in winter nets and this is almost a duckbill design to get the weight down.
I've nearly always had thick toes and low middles etc on my bats, but after using the old carbine over the winter,I've not felt the need for a lower middle, , now this may change once I'm outside on low slow wickets, but it does make sense what Paul Aldred and many others say.
I would say try and use a crictech sheet on a grass wicket, playing your normal shots etc
This might just surprise you as to where you actually hit the ball