README: k10_eval.py reads the query count from q0

The code release's k10_eval.py builds SetPoolN(Q) from the checkpoint since commit b8f84c3, so the note on scoring slot<Q> files is replaced, and the two new plan files are named as extra selection files for k10_eval.py cells.

README.md

@@ -114,6 +114,7 @@ five checkpoints in `q8_g4096_ckpt_plan.json` are the manuscript's rank rule app
 the worker saved with every checkpoint, the procedure that reproduces `rank_ckpt_plan.json`'s picks
 for the four-query runs. Campaign 2's entry format, plus `cap`.
 
-`k10_eval.py`'s `load_tower` builds `SetPoolN(4)`; to score a `slot<Q>` file, build `SetPoolN(Q)`
-from the shape of its `q0` instead.
+Since commit `b8f84c3` of the code release, `k10_eval.py` builds each tower from the shape of its
+`q0`, so it scores the `slot<Q>` files like the others. `c3_docfix512_ckpt_plan.json` and
+`q8_g4096_ckpt_plan.json` can be passed to `k10_eval.py cells` as extra selection files.