Don,
I have used "The Right Stuff" on two vehicles I have restored. It is a remarkable product in that it seals much better than others without seepage around bolts or edges. One characteristic is that it is also quite adhesive. Thus, I like to use it with assemblies that are not likely to be broken down, such as differential carrier for example. I predict you will be happy with the sealing qualities but will struggle when trying to remove the valve cover. It will really take some effort to remove it.
There are several theories on the best way to handle the valve cover gasket, from no sealant, to sealant only on the valve cover (since it is just a stamped piece that may warp as noted in the discussion above), to sealant on the head surface only, (since this is the most likely surface to weep oil). If you believe you have a high quality cork valve cover gasket I would suggest sealing on the head surface only with the "Right Stuff" and then you will be able to remove the cover easily to adjust valves, etc.
You will be fine with what you have done and it won't leak, but take your time when you need to remove the cover as it will be stuck pretty good.
Kent
