Although it say 3.2uf on the schematic I've usually found sprague 3.3uf or 1uf in akg C28s - which is an almost identical circuit but with miniature components
Here's some
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F322854487284
Although tbh ive always preferred the sound of metalised film if you can find one small enough - the haufe doesn't pass a lot of bass anyhow, but they're is something magical sounding about the low end on a c12, I often wondered if the shift to the haufe was to contain the low end a little, sub sonic frequencies were considered a large problem with the large diaphragm mics back in the 50s. A c12 with a Siemens 1UF PIO cap through the haufe just sounds wonderful.