To answer about percentages, not all of the honey or fruit will be converted to alcohol, some sugars not digestable to the yeast, tannins, and starches remain to give the wine it's flavor and mouth-feel. To compute the alcohol you would buy a home-brew hydrometer, and take a measurement before inoculating the yeast, and after you are finished. Subtract the two specific gravity readings, and most have instructions on using that figure to compute ABV or ABW.
Honey would be a great place to start, you'd make mead that way, mead is easier then fruit wine. Also you said the fewer ingredients the better. With mead you can go with only water, honey, and yeast. There are yeast nutrient packs used to speed up the fermentation, without them, it is impossible to predict how long until your mead will take to finish. You can tell when mead is finished when goes from cloudy to clear. One nice thing about going simple, is that the longer it for mead takes to finish, the better the mead will taste.
Fruit wine and Beer rely on waiting for fermentation to visibly slow (No more activity in your airlock) or by taking specific gravity readings, and noticing that they stop changing.
Another nice thing with mead is that you can boil it in the water, brewing it like beer to reduce contamination risk. Innoculate when it is below 70 Faranheit. Keep it where the temperature is steady and below 70 at all times if possible. With fruit you can't boil it as that will release pectin, and you'll end up with jam. Another thing that helps make mead easy is like beer, you get an accumulation of sediment on the bottom of your fermentation vessle after a few weeks. To prevent off flavors, you should have a second vessle, and siphon the wort/must (unfinished beer/wine) into the second vessle, and leaving behind the sediment to discard or reuse for future brewing.
Fruit wine requires about five transfers until the sediment production slows to negligible.
Auxin is right about the air-trap. I used a rubber stopper with a hole in it sized for the glass carboy and put a plastic tube in it, and I put the end of the tube in a bucket of water. CO2 can bubble out, but bacteria and contaminants can't bubble in. An added bonus to this method is if you fill the carboy up near the neck, it will blow the kreusen out into the bucket, so you can discard it. Kreusen is the crusty foam that forms in the beginning of fermentation. It's full of fusel oils, which add to headache and hangover. Cheap beer and wine allow it to fall back in, since it costs money on labor to remove it, increases contamination risk (unless you do it with the method I told you), and wastes some product. Since you're doing this yourself, why not go for top quality.
For yeast, you can just open a packet of champaign, ale, beer, or wine yeast when the must gets below 70 degrees. You can for higher quality use liquid yeast, or make your own by getting a stopper and smaller bottle (like a wine bottle) and heating up some malt extract or honey and addign the powder yeast, like a mini fermenter, then when it's really active in a few days, add the whole thing to the larger vessle.
As to adding fruit, or going entirely fruit, or what yeast to use (campaign,lager,ale,what style and brand of each), how much honey or fruit to add (less tends to give a dryer taste), what temperature to use (68 degrees to down as low as 50 depending on yeast, style and you'll get different flavor profiles fermentation at different temperatures) you're the brewmaster, the adventure is finding your own favorite recipe. I'd start out with something simple like mead when learning though. Here is one I found online.
http://www.epicurious.co.../views/Basic-Mead-201058From reading this, don't boil honey either, to not lose the aroma, and I'd add to that recipe, that just before adding yeast, shake the container full of must or wart vigorously for about ten minutes to make sure it is well oxygenated, what Auxin said about stuck fermentation is correct.
Good luck on your journey into the world of zymurgy!