What heat sink compound to use in a Musical Fidelity A1?


I'm doing some (hopefully) minor repairs on a 2008 Musical Fidelity A1. Removing the top cover reveals a 2" x 10" block thermally connected to the cover plate with white-silicon-grease-looking heatsink compound. There's quite a lot of it there, and I will need to clean it off and replace it before putting the cover back on.

What kind of heat sink compound should I use? My searches mostly turn up tiny tubes of compound to be used on CPU heatsinks. Or I see industrial materials. Any specific suggestions on what I should use? How much do you think I'll need for a very thin coat over that big of an area?
fishpatrol
https://www.mouser.com/ProductDetail/Aavid/249G?qs=L336xtxyopB3FeqhMjn9hQ%3D%3D

https://www.mouser.com/ProductDetail/MG-Chemicals/824-100ML?qs=X5SXQx2ktnOWsZ6FNh%2FXEQ%3D%3D

Clean the old stuff with the alcohol. Use a small blob of goop at one end and spread it thin with the plastic barrel of a Q-tip. You will need a lot less than you think. The thinner the application the better the heat transfer.
"The thinner the application the better the heat transfer", as long as any gaps between your sink/lid surfaces are filled/bridged.     Unless I’m mistaken; there are no fasteners, to hold the lid tightly against the heatsink, in the A1.
Thanks very much. The top cover has two screws that connect to the heat sink, so there’s some clamping force. I’ll try for a very thin layer. 
The usual mistake is to apply too much, which is less effective and makes a mess.

I know it has been a couple years, but I am also concerned about heatsink for my A1-2008.

How did your work go on your A1?  

Any advice you can give about refreshing the heatsink compound or other work on the A1-2008?

It is an absolutely amazing sounding amp, in a number of ways beats my OTL tube amp!