Basic strategies for maximum % saved solution for Hail 6,
without using the blocker
---------------------------------------------------------

1) First lemming must explode directly overhead the exit.

2) Lemmings 1-34 cannot be saved.  The falling alone takes too long for those
   lemmings.

3) Lemmings 35-80 can be saved.  Note that the later they come out, the more
   time they have to walk around to get to the exit.

4) So obviously, we want the first few savable Lemmings to be directly over
   the exit when the first lemming explodes, so they just need to do the falling
   to get to the exit, without any extra walking that they don't have time for.

5) The later savable Lemmings can afford to fall not directly over the exit.
   Depending on how late they come out (and correspondingly, how much extra
   walking they can do), they can be positioned increasingly away from the exit.

6) This is why the RR hits 99 during lemmings 3-34 (we don't care about them),
   and why the RR hits 99 more and more as we move on towards the later
   savable lemmings.
   

My solution:

("N: RR X" means as soon as N lemmings are out, change the release rate to X)

 0: RR 93
 1: RR 99
33: RR 69
34: RR 83
35: RR 31
36: RR 83
37: RR 99
38: RR 39
39: RR 99
40: RR 91
41: RR 99
43: RR 47
44: RR 99
51: RR 63
52: RR 99
59: RR 95
60: RR 99
61: RR 83
62: RR 99
69: RR 95
70: RR 99

Nuke when the last lemming out is about directly overhead the exit trigger.