I don't care for the poly ones.  Buy a handful of the rubber washers and keep 'em on hand in the tool box.

I'm new to the A-series engine and had a couple of questions regarding the valve covers:

Are the silicone gaskets reusable?

My covers had a single bolt with a hollow washer containing a rubber seal (one of the washers and seals is crushed). What is the best securing set up? A poly washer (like MM sells), metal spacer and T-bar set up?

Thanks all

I use cork/rubber. I keep sheets of it, and paper type material to cut whatever I need at the moment. I also use Gasket Shellac.

Recently, I had the same problem, leaking valve cover gasket. It was a good time to switch to the aluminum cover I bought. At my local auto parts store they ordered for me a cork and rubber gasket sheet. It was only 1/8 thick, I doubled it using silicone to adhere the two and the valve cover to the new gasket. The silicone gasket that MM is selling is $20 , The gasket material I bought was $16 and I'm able to get 4 gaskets at 1/8 thick.

As per dklawson, either will do. I lean towards the cork one.

I do a similar method with a slight variation on dk's method. I RTV the gasket to the valve cover and leave it sitting on the bench over night, with some weight on top, rather than on the head.

Either gasket is fine as long as the installation is done well.

I have posted my method several times before.  Rather than repeat it here... please visit the link below and look for my post.
https://www.minimania.com/msgThread/110203/1/1/Think_I_need_new_rocker_cover_gasket

I have switched over to the silicone ones. Just make sure you get the correct one for your valve cover. One type for stock steel type, slightly different one for alloy covers. Glue it to the cover but not the head.

I need to replace the valve cover gasket,oil leaking.What is the opinion of A series engine lovers, silicon or cork gaskets? Thanks