In the meantime i will tell you how best to do this in future.

Warning: It involves LOTS of hydrometer readings (Drop method)

(Use a standard syrup,This is normally 300 gravity (1 pint of water to 1kg or 2.2lb sugar)

Prepare your must and take OG reading and note it.

When this has nearly fermented out take another gravity reading and note it.(A)

Add about 4 oz of syrup (its not critical how much) take another gravity reading and note it (b)

Allow this to ferment out And take another gravity reading and note it (c)

Carry on doing this ie taking Gravity readings before and after Every syrup addition and note them down

The next stage is to subtract the the before and after readings after each syrup addition to get the drop after each addition of syrup.

Here is a made up example:

Gravity reading (A) is 1.005 So its time to add a dose of syrup,With the added syrup the gravity is now 1.015

and noted we let this ferment out until a gravity reading of (say) 1.005 is reached that means a drop of 10 points Which again is noted.This is repeated for every syrup addition.

Lets say in this case we only add the one dose of syrup so as is standard we take the OG -FG which in this case is 1.080- 1.005 which gives a gravity drop of 75 which equates to an abv of 10.19%

We now add the gravity drop due to the addition of the syrup which is 10 So 75 +10=85 which equates to 11.54% abv,So the syrup has boosted the abv from 10.19% to 11.54%

Lets say we make 3 similar additions of syrup each with a gravity drop of 10 points.In this case we have

75+10+10+10=105 which then equates to 14.2%abv

I am getting the abv values from a table,But in case you don't have one,Its simple just divide the total gravity drop by 7.36 so 105/7.36 = 14.26%.

This is the gravity drop method,Heavy on the hydrometer.