At the current HD LIL bandwidth rates Dish is using on 61.5 and 129, 105 would let them serve about 32 markets with HD LIL. 121 would be minus the bandwidth of the internationals. Since they will probably move all the standard definition LIL off of 105 and 121 to E10 at 110, they could move the HD LIL for small markets to the superdish and the current superdish customers would not even notice since they get 110 on SD anyways.
The whole HD LIL is a new item for Dish (and DIRECTV). I am sure Dish wants to have options ready if it turns out it is a hot seller in a year or 2 and 50 smaller markets on SD could be worth it to Dish (they would probably also make SD 4 satellites to pick up 129).
My prediction is that they will empty out the superdishes and wing locals to 110 on E10. Then they will use up the rest of the spot capacity of E10 to serve the top 50 markets or so with HD LIL. They will have 61.5 (spot), 85, 105, 121, and 148 in reserve to add more HD LIL if demand is there. Not to mention the 3 Ku-Aux slots they have reserved without satellites, the contracted satellite from ses-americom that they have placed a downpayment, and Ka slots they have.
Dish now appears to have more capacity than they can use. It will be interesting to see what they do with it all.