Preparing CdSe electrodeposition bath

What is the best way of preparing an aqueous solution containing 5 mM 
$\ce{CdSO4}$, 1 mM $\ce{SeO2}$, 0.5 M $\ce{Na2SO4}$ and adjusting pH to 3 by adding 0.5 M $\ce{H2SO4}$? 


What is the conventional way of doing it (in industrial chemistry or simply just the labs)?


