You can also get bushings from Vintage Vibe: https://www.vintagevibe.com/p-484-synth ... hings.aspx They're cheaper than Syntaur, and for $1 more, they'll come lubricated,which is important. I've always ordered mine from VV, and never had any problems. If you use the wrong lubricant on bushings, it can lead to keys sticking.
I have tried several types and the only ones that really lasted well are those from Archive sound.
The other option which I used on my PPG is a completely different method of repairing a Pratt Read action but the result is far, far better than any normal rubber bushings but more time consuming to install. The result though is an action that feels an order of magnitude better than even the best Pratt-read action with new conventional bushings. Available here: