Quick note, when calculating pot odds, you don't add the amount of the call to the pot. Villain had to pay $7 to win ~$23, not $30.
True.

I generally find percentages easier to use than fractions (comparing percentages is easier than comparing fractions).

via odds, villian has 23:7 or about 3.3:1.
1/4.3 ~ 23%
via percentages, villain must invest 7$ into a $30 pot
7/30 ~ 23% villian's "pot equity" (I may be using that term incorrectly)

so it's saying the same thing. Plus I find it easier to remember the guide of (percentages)

2*(number of outs) 1% ~ chance of drawing out

So for FD, about 18-19 % (have no idea what the guideline number is for pot odds though math says it's a shade less than 4:1)

Calculating percentages also has the advantage of memorizing less and being able to account for weird situations with a "nonstandard" number of outs such as a OESD with 2 overcards and a possible flush draw where you hold none of the suit of the possible flush.

Incidentally, how often do you end up showing down TPTK? I agree it can be tricky enough to play out of position.