Cary 805C Coupling caps modification

I am thinking about changing the coupling caps on Cary 805C from original stock, Audio one, to Mundorf Silver in oil capacitor.

How many capacitors do I have to replace ? What are the values ? I believe that Mundorf has high enough voltage for this. Any inputs are highly appreciated. Thanks.
Hi Gunsur,
You may try to find a schematic diagram online. Failing that, it's possible that Cary would be willing to provide the cap locations and values. An experienced tech familiar with tube circuits could quite easily point them out to you-they are connected from one tube pin to ground- usually with a resistor in parallel.
look on your old caps the values are on them. You need 4. It is a simple matter to swap caps but it does require skill. Go slow and carefully. or have it done .
You can get the schematics from Cary, but it depends on how old the amps are. If still in production, forget it, they won't give them out. Otherwise, it should cost $25 dollars for a download. Well worth it, believe me.
Gunsur, actually coupling caps are connected between tube plate and the next tube grid.
Most coupling caps are in the range range from 0.1 uF to 1 uF. Since the input gain tube and the driver tube usually run off a 300 to 400 V DC supply, 1200V Mundorf caps will do fine.

This tweak is for a qualified tech only, because the output tube (and many surrounding circuits) use very high voltages. My guesstimate is 800 to 1200 VDC, AKA lethal if touched.
Thanks for all your feedback. I will take your advice to have the experience technician to upgrade.

I find out from Cary it is 0.22 mfd, but I believe I need total 4 pieces, 2 at the tube and 2 at the power supply assuming they bridge the capacitor. Thanks.