Its less of a recipe, and more of simple math. We need to know how to cancel units here, and thats IT. Heres some helpful (and brutally simple) equations and constants to remember:
mg/ml x ml = mg
1g powder = 0.8ml (realistically its anywhere between .7-.85 but more usually 0.8 for long ester liquid stuff)
We know we want 10ml of 200mg/ml test mixed with 300mg/ml EQ (500mg/ml combo). 2/20 ba/bb ratio.
mg/ml x ml = mg
200mg/ml x 10ml = 2g test
300mg/ml x 10ml = 3g EQ
Total powder = 5g
Total volume = 10ml
(-) 5g x 0.8 = 4ml (powder volume)
(-) 10ml x 0.02 = 0.2ml (BA volume)
(-) 10ml x 0.20 = 2.0ml (BB volume)
Oil volume = (10 - 4 - 0.2 - 2)ml = 3.8ml
Mix, heat, stir, clear, fliter, enjoy.