I see so many posts on this site by people who are literally freaking out because they got beat up & lost "beaucoup" units! I say this is RIDICULOUS.
I like to think of my MAXIMUM bet as my "unit", and my "waiting" bets as merely FRACTIONS of a unit. After all, in the final analysis; the max bets are the only ones that REALLY matter anyway (at least to ME).
If I'm spreading $25 to 2 x $500, and I get stuck a thousand bucks; I look at it as though I'm only stuck ONE unit, rather than 40. For one thing, it makes for a much easier pill to swallow, and FRANKLY; it's a more accurate measure of my results ANYWAY.
IMHO; to think of a "unit" in any other way is like comparing apples to oranges.