If you want the finish to stay nuetral, clean, and colorless. The water base polyurathane's are going to be the best bet. Lacquers, oil's and especially varnish all carry an amber tone to enhance the grain and give the wood a warmth. All of these are going to become a more golden to amber colour with age. Water white lacquer's are less amber and designed to be now yellowing, so you have less aged look over time. The blonde shellac's can stay pretty clear but basically anything made with petrolium type products and distilates requiring alcohol or a thinner for cleanup is going tone out with age even when sheilded from UV.
The water base poly is easy to apply, easy to clean up and is as durable as the best of anything. The biggest problem with the water borne finishes, be it poly, lacquer or varnish. Is that the water borne does not do exactly what you are looking for. They have no amber tone unless it is added. They dont pop the grain in high figure woods and veneer, and they wont yellow, amber, tone out or show virtually any sine of age to give a petina or look of age and depth.
Get your self some Minwax water base poly and your birch wil stay as clear and blonde as you like. Use a non yellowing silcone wax after your all done and stay away from any paste wax or similar product that will deposit a film that can tone out.
Spraying finish is always best but if your going to brush then great results can be had with care. Buy a good brush and keep it clean as new and it will last a long long time. do some research on brush care. strain your finish as you use it. Dont use the finish out of the original can. Open the can, pour out what you need and close it up again.
The first coat is going to rais the grain a little. if you sand with 400 it will be less. It really doesnt matter because you HAVE to sand poly in between each coat. Poly and varnish have 0 burn in and require a mechanical bond from one film to the next. You must sand with 220 in between each coat if you want to achieve the best finish. So sand off the first coat since all the wood fibers will get locked down in all kinds of kamasutra type positions. apply a second coat, sand, apply a third coat, sand, apply a fourth coat if you like a smooth build. 3 coats might make you happy and it's a commercial standard. 4 or better coats with good sanding in beteen to make sure the surface is leveled and uniform can look dynamite.
If you want glossy gloss then your last coat needs to be heavenly perfect or you have a lot of rubbing to do, but if this type of "piano" finish is what your after this isnt the right stuff. Most folks like a fairly smooth satin with just a hint of gloss to it. For this I always use a gloss finish and rub it down to a satin. Sand your last coat with 400 paper, now steel wool using 0000 steel wool, and then apply wax.
One last note if you use a water borne finish. Do not use any stearated sand papers. Do not use any steel wool in between coats, and any of the scotch bright pads for rubbing and sanding are also a bad idea.
Bill