If you will be staining, you want de-waxed shellac. The regular Zinser Orange Shellac contains wax, and it will prevent your stains or finishes from sticking. Zinser makes a seal coat shellac that has had the wax removed. It is more clear with no orange color, so your stain will have the color that it's supposed to.
Be careful when storing the seal coat, since over the years I've had 2 cans develop leaks a year or more after using part of the can and then putting it in my paint cabinet. What a mess. By the time that I found it both times, the can was completely empty, and my paints and stains were all glued to the shelves. I now place these cans in zip-loc bags before putting them in the paint cabinet. If you ever enter your shop and smell alcohol or shellac, run to your paint cabinet to save what you can. I've never had this happen with anything else, just the Zinser Seal Coat, and I've heard of it happening to others too.
Central North Carolina