I have found that on some of the big beers splitting the Mash actually gets you a higher overall effiency. It takes longer but it helps.
Also, I tend to go higher than the typical 1.25qt/lb.
I did a barley wine and used 1.75qt/lb for each mash and reduced the sparge amount. I ended up after 3 mashes (10 gallon batch) with a 1.098 OG, I then added a bit of Corn Sugar the 3rd day in to fermentation to bring it up to 1.102.