Reddit mentions of Digital Luxmeter/Digital Illuminance Light Meter with LCD Display 0.1-50,000 Lux Range

There's nothing wrong with your approach but spacing in this context is when people use uncut 5m strips.

A narrow spacing would have a tight ring with the LED strip. As you wrap the strip around the inside of the bucket there would be no space between the strips. The problem with this is that all the light is concentrated to a narrow region of the plant at higher lighting levels.

But, lower lighting levels can actually be more photosynthetically efficient (this is why shade cloths are used in a lot of green houses). The two main reasons why higher lighting levels can be less efficient have to do with non-photochemical quenching and photorespiration.

So it is more efficient for the plant to not blast the plant as hard but also have the lighting more distributed so that more individual leaves receive light. Unlit leaves below a certain lighting intensity, known as the compensation point, start consuming more resources than they produce. This is part of the pressure flow hypothesis and is the basis of why some people might defoliate a plant (remove some leaves- as a beginner I would not do this since it is often over done and haphazard).

So with a 5m strips it's typically better to have an inch or two between the wraps to spread the light out and illuminate more leaves.

Don't fret! You can still use your LEDs. You can do a bit of trial and error or even better buy a cheap cosine correct lux light meter (lux meters should only be used with white light, not color LEDs- you will get very wrong measurements with color LEDs) so that you can dial your spacing for very even lighting. The light sensor in phones tends not to be cosine correct and can therefore give some real bad readings.

It looks like you have some experience soldering so you actually have some more flexibility in how you set up your side lighting instead of just a continuous 5m strip.

If one is working with white light and plants, the best investment one can make is a simple, low cost light meter to set everything up.

https://www.amazon.com/HDE-LX-1010B-Digital-Luxmeter-Display/dp/B00992B29I

I would say it is viable, but LED bulbs would be better than CFL. Keep in mind that you can raise the plant closer to the lights. The best way to know for sure is to follow /u/SuperAngryGuy advice, get a Lux meter and read his guides at /r/HandsOnComplexity.

Well i test for LUX and calculate par based on height, spectrum used and lux to come up with the average par. I'm not the most experienced person for indoor grows since all my other grows have had solar power. With LUX and watt meters while the data i collect might be off its still something to go based on for future grows.

Digital Luxmeter/Digital Illuminance Light Meter with LCD Display 0.1-50,000 Lux Range https://www.amazon.com/dp/B00992B29I/ref=cm_sw_r_cp_apa_i_uAuEDbEAF4NWN

I own this device, works like a charm
https://www.amazon.com/Digital-Luxmeter-Illuminance-Display-0-1-50/dp/B00992B29I/ref=sr_1_13?ie=UTF8&qid=1527670303&sr=8-13&keywords=lux+meter

You can find them cheaper than is, but this is the first hit that is exactly mine.

You are going to need something like this https://www.amazon.com/Digital-Luxmeter-Illuminance-Display-0-1-50/dp/B00992B29I and to fine tune each one manually.

Well if you aren't using flash and just need ambient, an iphone meter (get an attatchment) or cheap meter (http://www.amazon.com/HDE-LX-1010B-Digital-Luxmeter-Display/dp/B00992B29I/ref=sr_1_14?ie=UTF8&qid=1416841101&sr=8-14&keywords=light+meter) may work well.

That meter will give you lux. You can print a quick EV conversion chart and tape it to the back.