The standard covers are well known for being weak. Any "hole drilling" you do it only make matters worse. Rattler's picture of the nearly-failed Tecmoto one illustrates perfectly what happens. The end of the fairing gives way and the clutch cover beares the grunt. The problem with any metal clutch cover that has openings in it, is that ones "dented" the shear off the posts. Look at Antonye's picture. See how far the springs protude from the pressure plate? If that clutch cover gets "dented", which it will since it's a drilled stock cover, it will act like a saw blade on the spring posts.
I've had several lowsides on the track and have never damaged the clutch, even in my recent off at Oulton Park (where by the way the crash bungs were utterly useless and did more damage than good). I've had great success by reinforcing the fairing with additional kevlar around the area where is overlaps the clutch and using a "reinforced" carbon clutch cover. Yes, not all carbon clutch covers are made equally. One of the best features of a good carbon clutch cover is that it "springs" back and so won't stay dented and shear off your spring posts. I know some of you have had damaged your clutch with carbon covers. I use this one:
CarboTech part number MODU940611
They also make a waterpump protector for those left hander lowsides: MODU940519
I think Rhencullen is the UK distributor but JHP used to do them as well.