Going by the numbers you quoted, yeah, the Petrof would be cheaper than a C3, and the Estonia 190 would be in between a C3 and a C5.
If you find yourself liking the new Estonia 190 more, be assured that you'll be getting a good piano. There is no inherent problem with new Estonia pianos that I am aware of. Besides, depending on the dealer and the market, there might still be room to negotiate on the $24,000 asking price. Personally, I also like the Estonia 190's tone.

It may be possible to buy the cheaper Petrof and then hire someone to get it up to shape and still save money -- $5000 can certainly achieve a lot. Questions are: Are you confident enough to pick a Petrof with that potential, and, are you sure you can find a piano technician compentent enough to take the piano to where you expect it to be?
Of course, if you can find a Petrof that you already like in the showroom -- then just buy
that one (take down the serial number and insist on
that one being delivered), then you won't have to pay much for voicing work afterwards. Probably still need to budget for some minor voicing and regulation work (a small fraction of the $5000 difference), but you reduce the risk of buying a Petrof that may never develop the kind of tone you want.
[ EDIT:
As for acoustic environment -- smaller space will make the piano sound louder, hard surfaces like hardwood floor, concrete walls, etc. will make the piano sound brighter and louder; soft carpet/furniture, soft wall covering, curtains, rugs, etc. will make the piano sounds softer/mellower.
If two pianos as placed "side by side," then remember to close the lid on the piano on the right when you play the piano on the left -- to avoid sound from piano on the left getting reflected by the lid of the piano on the right. In general, when playing piano with the lid open, the lid should open towards an empty space.
Also don't forget to test pianos with lids CLOSED as well OPENED at various positions, and with the music stand folded as well as in upright position -- the music stand will change the way you perceove the sound, and in the home, there is a good chance that you'll be playing the piano with the lid closed -- so might as well test for those conditions. ]
Good luck.
