Gripping Larger Stones

I have a comp. coming up here in early November, and I have a problem. The stones being used for the event are a good bit bigger then I have ever had to load; and when I train with stones of the same size, I can hardy even grip the piece of shit. Like its not extremely heavy, its just the size of the damn thing. Any ideas for ways to improve gripping for very large stones? Any advice is much appreciated.

I find that as the stone increases in diameter the bear hugging becomes supremely important to get it into my lap. I have to remind myself to squeeze the stone as hard as possible before the initial pull from the ground. Once lapped I put my arms over the top of the stone before standing and shotting my hips under it.

Pin wheel curls DC Training/Pinwheel Curls - YouTube
I try and touch my opposite shoulder with the DB

And seriously…more pec strength! Stuff like wide grip bench helped

Be sure to tacky up well, squeeze and rip it up.