If you are absolutely sure of the resistances you need (I wouldn't trust the simulation that much), then you can buy 1% resistors and parallel a pair for each note. Here is a calculator from TI for calculating individual resistors in a parallel pair, but the site is temporarily down: **broken link removed**
However, I would buy a bunch of trimmer resistors (one for each note) and use them either individually or in series with some near-correct fixed resistors, such as 100 Ω, 220 Ω, 333 Ω, etc. plus a 100 Ω trimmer. That way, you can tune the piano too.
John