I would first decide on what type of tank I was going to run.High energy(High tech) CO2 enhanced, or low tech non CO2 and read up on both.
If I was new to planted tank effort's, I might select low tech method where not much light is needed,no CO2,and minimal maint.
A wise man once told me..'choose a method,and learn it well. then try another.
Everything happen's very quickly in CO2 enhanced tank's with higher lighting and is steep learning curve while trying to get CO2 dialed in ,good distribution ,good flow,regular fertilizer routine to achieve desired result's. (algae happen's quickly also).
Low tech method gives one a chance to observe thing's at a slower pace,plant's get buy with less light,no co2 ehancement,fewer water changes (although more doesn't hurt),and fertilizer's maybe once a week or every two week's.
Try not to put too much into those who say,,, "well this work's in my tank whether it be CO2 injection rate,, fert routine,,, lighting period,etc for their tank is not your tank, and what may work for them might not work for you.
Choose someone who is running a tank like you desire, and seem's to be knowledgeable,and follow their advice rather than trying to use bit's of everyone's advice = much confusion.
If their advice work's,,well then good. If not,,,at least you can say you tried and followed their suggestion's.
Best advice I can offer is ,,study what aquatic plant's need to grow, and you will spend less time studying /exploring way's to stop algae.
6700K bulb's will work fine as will nearly any bulb's.More important that you like the way the light/tank look's.
Plant's are very good at using what light is available and there is no magic spectrum that will increase or decrease the health of the plant's.