Odds are your wood is not Lyptus because of the properties you describe. Very few sources of Lyptus are trustwothy and ship whatever is plentiful at the moment. That isn't important if you are satisfied with the appearance. What is important is the combination of products used to finish it. It is real simple for the novice to choose stains and/or topcoats. First prioritize your preferances for topcoat. In this case,beauty and water resistant with wearability not being nessary. You mentioned MinWax which is my reccomendation for the novice because it is simple to use and yields good enough results. So Minwax Wipe On Poly Satin it is. Now you choose stain,Minwax Wood Finish. Both products are oil based and paint thinner clean up. Miwax offers many products,all except Polyshades are good products when used as directed. Choose another brand if you like but NEVER mix and mingle brand names until you gain enough experience that you aren't asking what to use like you are here. Whatever you use,follow the directions printed on the label to the letter,again until you don't need advice on what to buy. It's important to understand that far better products are on the market but they are difficult to use until basic skills and methods are mastered. Pros luv telling green horns about their secret witches brew without considering the specialized techniques required in applying it. I have heard many swear by their concotions eventhough it flys in the the face of the world's finest experts. It's fun trying to invent better mouse traps after one becomes bored with established ways but it's asking for trouble a novice isn't prepared for.

The properties of warping of wood have been thoroughly studied and understood scientifically. Casual observations relating warping to finish (or lack thereof) are faulty. My mother had a butcherblock portion of counter for over 30 years, never oiled or finished anywhere, that never warped. I've had boards that warped and others that didn't, some finished, some unfinished, some partly finished. It's not the finish. Wood tabletops, countertops, decks, etc. are exposed to more water on the top than the bottom, causing the top to swell and try to expand. But the wood's thickness remains stable and prevents this. The cells of wood on the top of the board become compressed from their original cylindrical shape (like a soda straw) into an oval shape. As it dries out, the wood cells do not fully regain their original shape, so the top shrinks, pulling the board concave. This is called "compression shrinkage." Therefore, finishing the bottom of a tabletop or countertop will not prevent warping. Warping will always be cupping of the top due to swelling from wetness of the top and subsequent compression shrinkage. If lack of finish on the bottom caused warping, you would see the tabletop bow, not cup -- but this never happens. Or think about it another way: what liquid is going to soak into the bottom of your installed butcherblock counter, that a finish is going to block? It's not going to happen. And no finish blocks water vapor (from humidity in the air), only slows it a little bit, so this would make no difference in protection either. So if you want a tabletop or countertop not to cup over time, there are two things to consider. The most important factor is the quality of wood making up the butcherblock: the size and shape of the wood cells, their density, how the wood was cut in relation to the growth rings, and how it was dried. Butcherblock made up of dense, old-growth, quartersawn boards slowly air dried is going to hold its shape (even when totally unfinished), while strips of young, low-density, plainsawn boards are going to warp easily. Second, keep the top as dry as possible. Don't let liquids soak into it, or use a water-resistant film finish if you expect liquid exposure. It's not the finish on the bottom, it's how dry you can keep the top, that helps prevent cupping.

I hope you have some samples for testing, or can detach and turn the countertop over, because just sealing can darken a finish. Also, if you don't seal the underside, they can warp. My IKEA numerar slab, sealed only on one side, warped when the humidity rose during the rainy season and there was almost an inch of difference between the edges and the center. It eventually straightened out when the humidity went back down, but it's better to prevent it. My alder countertops went from pale blonde to a reddish brown with just untinted tung oil (Waterlox). I saw the color change and canceled plans for staining it. Try the sealant alone. For an eating area, any finish will do, but consider something matte that will not show the inevitable scrapes and nicks as badly as high-gloss does. Then try several stains. You can buy tiny test packets of stain at ACE and perhaps other stores. It's convenient and cheap.

I’m just worried I’ll mess up the nice rounded inside corners. The sander is too big to fit in the curves anyways. Yea, I’ll stain the top and put on the Watco. I already finished another piece of butcher block for the other side of the kitchen so I kind of have to keep going. Then, I guess I’ll make sure to have cutting boards for any food prep I do, which I was planning on anyways so the counter didn’t get too scratched. Maybe in another couple of years I‘ll redo it with something better if it turns out a complete disaster.