A score field and a token in your email referencing the value in that field could work, but the trick is every lead would need the same value in that field.
You would create a Number score type field and set its value to the current number of the week in all the lead records (e.g. 24 for this week). Then you would create a smart campaign, that is scheduled to run at the start of each week. It would have a Change Score flow action that increments the Number field by 1 as in the following screen shot.
You would follow a similar process for the Volume field, but the smart campaign would only increment its value by 1 each year.
The trick is every time you add a new lead, you will have to ensure that the values in these fields are set to the current values, which likely means that every week you will need to update a smart campaign that sets these values in new leads, so I'm not sure that this approach solves the problem of rembering to increment the Volume and Number value each week / year.