PSP fonts - replacement font?

[Sarisa81]

I'm trying out some free fonts noted as having large x-heights.

Merriweather: 0.546. About the same as DejaVu. Good coverage, but DejaVu has good coverage too.

Actor: 0.503. Odd for a font that claims to need lots of leading. Low cap height with high ascenders?

Poly: 0.473. I shouldn't have had high expectations for a serif. (Also, it may have been designed with a lot of extra room above the letters for accents, since it's intended for American languages.)

Signika: 0.495. Again, this is NOT a large x-height!

At the rate this is going, you might end up cutting down DejaVu Sans to fit, or adding accents to Orbitron. (As-is, DejaVu Sans will be a big improvement over Liberation Sans, but it's not metric compatible.)