I use se1 and se2 (if you have an expander that you can begin with a number, you could make it 1se and 2se).

se1 = himself
se2 = herself

I try to keep down the numbers in abbreviations, and have a little different system for this:

xy male
xx female

y man
x woman

h he
s she

i his
e hers

yz himself
xz herself

and also:

mf myself
if itself

of ourself
oz ourselves

uf yourself
uz yourselves

tz themselves

a few interesting choices - but what about
if, i, and of, which are frequently used regular words?

And if you are using IT, why abbreviate he, since it is still two key strokes (the h and then the expansion key)?

The beauty of a using a real expander is that one doesn't have to worry about duplicating actual words in your shorts, since you type a marker key after the short rather than hitting the space bar. Typing "i space" gives me I, and typing "i;" gives me his.

As far as he being abbreviated: "h;" is two keystrokes to get "he space", and
"he space" is three keystrokes to get the same result. (I use IT with automatic spacing and capitalization on. I have separate keys assigned now for a decimal point and a non-spacing/capping colon, so there are no extra keystrokes involved using a marker key rather than the space bar to expand.)

I did note elsewhere that I generally don't abbreviate two letter words. The only exceptions are a very few of the 100 most common words. He is the 13th most common word in written English and the 18th most common in spoken English (see below). I certainly agree that if you have a better use for "h;" and "m;", there is no need to abbreviate he and me. I find the personal pronouns are so constant in dictation that it is worthwhile to get them as short as possible, since one won't have a phrase for everything that includes them. I also prefer consistency in my abbreviation schemes insofar as possible. It is admittedly very much a matter of personal taste. I just posted the whole layout so people could see how I had handled all the pronouns, as I was afraid that just writing that I use "xf" and "yf" for herself and himself might have left people without a clue where I pulled those from.

Word Frequency of the Top Twenty Most Used Words found in Written English
the of to in and a for was is that on at he with by be it an as his

Word Frequency of the Top Twenty Most Used Words found in Spoken English
the and I to of a you that in it is yes was this but on well he have for

You are still saving one keystroke for the spacebar and the one-key savings also add up fast.

When adding short phrases that begin with it, is, in, if, of, I begin my short form with it, is, in, if, of to differentiate between them, still saving the stroke for the spacebar.

Cheryl