My advice is to look at doing it 1 of 2 ways
Option 1, Put together a loose collection together one of each figure including major variations e.g small head / large head Han Solo.
Easy to do as there is no real research commitment needed bar finding the funds as all figures can be found mint and complete on any day of the week really. Even Blue Sangs VC Jawas etc.
Option 2, Work at one or a few figures at a time and study, learn and collect all the variations for that figure that you can find.
Once you have exhausted the options are are waiting on the harder to find or more expensive variations move to a second figure and follow the same pattern.
They were the choices i was faced with regarding loose and i am very happy i went down the second option!
One thing i will say is wherever possible only buy complete figure with original accessories!! Its only costs a lot more further down the line!
Plus take my Vader variants a lot of the Vader variants have very specific types of Sabers / Capes you cant just add any saber or cape to the figure later down the line its the same principle for many other figure variants.
Just my thoughts hope that helps lads
***THIS PROFILE IS UNMONITORED*** Please contact Darthberizing