Well, being a software developer for a quarter century of my life let's approach this with logic
You buy a couple of bottles of your favorite
juice just like you do now.
At the same time you buy your DIY gear and you DIY the juices you mention above and you put them back to steep.
You continue to use your purchased
juice for the next 2 weeks at which time your steeped
juice is now ready to go.
You switch to your DIY juice and create another batch of DIY at the same time so that in 2 weeks it is now ready.
After this short process you are completely off purchased juice and completely on DIY juice (if you so choose).