Ok this is what I would do:
Take a hydrometer reading when you get the bucket of juice home, record that. Then if you can take an acid test or ph test, do that, normally the juice buckets are balanced but you should know what the acid level is. Ferment to below 1.010, then rack to carboy, leave it until fermentation is done, when hydrometer reads below 1.000. At this time you can calculate your ABV. Then rack again, add k-meta at this time and let it age in the carboy with an airlock on it. Rack every 3 months and add k-meta at that time, until your wine is totally clear, then bottle.
The advise you were given has a 50/50 chance of working out that way. Personnally I don't like those odds, so I would try my best to have a 100% chance of coming out good.