Hi PSUalum and Welcome to TFF!
1) Judging test result colors: My first choice, for practicality, is to put a hooded incandescent light source (eg. an incandescent lightbulb in a metal shade like a desk spotlamp) between me and the sample, which I hold at arms length with the test tube against the white portion of the card. I look at the center color portion, not the portions of liquid shadowed by the tube curvature and I always try to keep in mind I'm matching "hue", not brightness. I use incandescent because most forms of fluorescent add green. Daylight can also be quite good but I find that less practical on a regular basis.
BUT, more important than the above and harder to learn is that often a really detailed reading is NOT important! In fishless cycling we really just have a few key feedback hints we are looking for. In your case, you simply want to be sure the ammonia doesn't have a chance of being high enough to look anything like 8ppm (where a different species of bacteria can take hold) and you don't want it super-faint. Anything in the 2 to 6ppm range roughly is going to work out ok, so you're already probably trying hard enough. (And to continue that thought, a lot of the feedback we want is just whether the substance "is there or not" and rather roughly at what level.. often our log will help us see the trend even when an individual reading seems confusing or off. Having an aquarium notebook and especially a daily log of results during cycling is very important.)
2) Heater requirements: This too is another rough analog sort of thing. The general starting rule of thumb is 5 watts per 1 US gallon (meaning you're doing fine with your 25w) but the assumption is that the aquarium is sitting in a room of a comfortably heated human household. When hobbyists place tanks on sun porches or in garages or basements, they have to re-think the heating aspect since the heater may have to work harder or the situation may be even more extreme and require insulation. A 25w is the practical lower end and thus serves as what you need for a 10g, however it's also interesting to know that the rule of thumb is also based on not having too much power present such that if the thermostat got stuck in the on position the fish would cook. This is less a concern in recent years I think but can still happen occasionally. Also note that numbers on a heater don't represent reality, you have to use a separate (spirit, whatever) thermometer to "set" your heater (the numerical dial can often be re-seated on the rheostat once the real temp has been established, the going on of the little light being your sign that the internal thermostat is at the setpoint.)
3) Tank lighting: Two 10w tubes on a 10g will put you right at the high end (actually a bit too high in my opinion, but I'm not sure how I'd cut in down practically) of the brightness you want. My assumption of course is that with a common 10G you are not planning a fancy planted setup with pressurized CO2 equipment (and you mentioned the plants and said moderate.) You will possibly have to counteract your extra brightness with a bit shorter photoperiods (periods when your timers have the lights turned on).. Ideally I'd consider two simple lamp timers if your tubes are in separate strip fixtures and then you can do step-up, step-down with only one lamp going for beginning and ending periods of the day more or less. Light is the "driver" of all the other plant issues, the brighter it is the faster everything else goes and the more difficult it becomes to control things, but the right brightness is also of course much needed. If you've already obtained plants, you will need to feed them (and right away) because they will quickly starve in a new tank. You will be doing what we call "low-light-technique" (the 1 to 2 w/g range) and will need to feed them liquid carbon and a low dose of macro and micro nutrients (again, this is my opinion and not gospel as many may feel you can get by maybe with a pinch or two of fishfood (this supplies a lot of nitrogen phosphorus in my experience, two of the 17 nutrients they need) until the fish begin fertilizing them with waste (again, giving them some N and P, in my opinion).. if you let us know your location (ie. USA, UK or whatever) then we can advise further on ferts commonly used. And an idea of your water hardness will also help. Fishless cycling with plants in is a tad trickier in that you need to minimize light (since light plus ammonia equals algae) but it's quite do-able and we'll help (others will help as I'm off to a swim meet this weekend, lol.)
~~waterdrop~~
ps. sorry you got one of my long ones while drinking coffee!
Could I be cycling this quickly? 
