Using MongoDB for time series data is a very well document and established use-case, with official whitepapers and presentations. Read and watch the official documentation from MongoDB before trying to invent your own schemas for time series data.
In general, you'll want to create "buckets" for your timeseries data:
DailyStats.insert({
"date" : moment().format("MM-DD-YYYY"),
"dateIncrement" : moment().format("YYYYMMDD"),
"dailyTotal" : 0,
'bucketA': 0,
'bucketB': 0,
'bucketC': 0
});
And then increment those buckets as data feeds into your application. This increment can be put in a Meteor Method, a collection observer, a REST API endpoint, and various other places.
DailyStats.update({_id: doc._id}, {$inc: {bucketA: 1} });
For a more complete Meteor example, see the examples from the Clinical Meteor track:
Realtime Analytics Pipeline
Clinical Meteor - Graphs - Dailystats