Without much detail regarding your recipes, your answer is going to be a bit shallow and lacking in detail. Regardless, here goes nothing:
First off: Glass or plastic makes no difference in today's home brewing world as studies have shown plastic carboy's oxygen permeability is a non-issue compared to glass.
Secondly, most Lambics' yeast contains wild Brettanomyces yeast, which is notorious for requiring longer fermentation schedules due to its prolonged fermentability, especially if blended with traditional Saccharomyces yeast. It can ferment sugars that regular ale/lager strains cannot, so long as it can feed off oxygen to do so. If you plan on fermenting a Lambic, plan on at least 12 months of maturation before going to bottle. Any shorter and explosive bottles are a real possibility.
Also worth noting, since wild yeast and bacteria often times have a mind of their own, it is not uncommon for Lambic brewers to blend several batches to achieve a similar taste between their bottles. You may consider after a year or two's time, when the beer matures, to blend your two (or more) batches together to find a perfect harmonious blend, then use that ratio to bottle with.
If you're interested, here's a podcast from the folks at BeerSmith and Michael Tonsmeire regarding sour/wild fermentation.