Hi Bartek,
Your project sounds really nice and I wanna be part of it.
Let me introduce myself...
My name is Andrés González, I'm from Latin America, I speak Spanish (native) and I strongly believe that I can provide you with a great/high-level outcome for Spanish.
I have good hardware/software (even though you need no edition) for voice-recording. I have a Zoom handy recorder H4n, and a coulpe of mics. The audio quality is great, free of background noise, and high fidelity.
I would love to attach a small sample in this message but unfortunately I can't (there's no <<attach>> button). So, please send me a message via chat and I'll send you a sample there.
Regarding my Spanish...
I have a soft accent, clear pronunciation and intonation. FYI... I live in Colombia, close to Bogotá. This region has no strong accents such as the coastal zones.
Looking forward to work for you!
Best regards,
Andrés González H.