splitting apart a changeset

[Ernie Rael]

Given:

$ hg log -l8 -Trevsum
1543:fed597e360a9 draft Fix stuffReadbuff(":someCommand\n") issue, 
required IDE restart
1542:8d1ea8b127b1 draft annotate source with "// DONE" for end of line 
Segment issues
1541:cefdab9bbdad draft Better skipwhite(iter) implementation. 
Misc.skipwhite tests.

I want to split 1541 into two changesets: algorithmic change and tests. 
In this case I need to take one file (algorithm) out and into it's own 
changeset.  I've never tried hg split, but I'm wondering if that's the 
best/simplest way to go about it.

    hg split -r 1541 src/com/raelity/jvi/core/Misc.java

But reading the help, I'm not sure that's what I want. The statement

    The files that doesn't match will be gathered in the last changeset.

Alternately I'm thinking about

hg up 1541
hg amend --extract src/com/raelity/jvi/core/Misc.java
hg commit -m 'algo change'
hg evolve

Any comments/suggestions?

-ernie