I've only ever had two stuck mashes, one was half wheat and the other was yesterday.
As you crush finer, you may need to pay attention to flow rate and husk quality. That means that you may need to start you flow slowly before increasing the runoff rate to prevent compacting the grain bed and malt conditioning to prevent your husks from shredding.
Ive noticed no noticeable difference in efficiency based on the water to grist ratio...
I generally get 85% efficiency at 1 qt per lb and 1.5 qt per lb and everywhere in between.
If you get 85% efficiency, then you won't see an increase from a thinner mash because there is really no room to increase. The benefit is limited to brewers who get 75% or less, since those brewers are probably not getting complete starch conversion.