Definitely a more accurate way! First of all you're going to need a digital scale. The rough rule of thumb is figure 1/4 tsp per capsules, so 12.5 tsp for the whole batch of 50.
Next figure out the desired volume that you ingredients will take up. So if you want 200 mg/cap, and there's 50 caps, and the density if 1/4 tsp = 500mg, the way I calculate it is 0.2g * 50 Caps 10g. If 1/4 tsp = 500mg, that would be 5 tsp right there.
To give you an example, here is my roughwork for my last batch of caps;
300 mg/cap GTE. Total = 15g,
Coleus. Goal = 80mg/day/20%= 400mg./3 = 6.67g
GSE: 100mgx50= 5g
Raspberry Ketones: 100mgx50= 5g
Volume: GSE= 8.33
Coleus = 10.26
GTE= 15/0.7 = 21.43
RK: 5/0.4= 12.5
My volume calculations are a bit different because I just divide the mass of the ingredient by the density and make it all add up to 50 (capsules).