Dissolving to Create a Solution with Ethanol If at 95% Ethanol can dissolve chemical X at 1mg/1mL then theoretically if you have 500mg of chemical X you can dissolve it in 500mL of $\ce{EtOH}$ to get 1mg/mL correct?

My question is, if you have 75.5% $\ce{EtOH}$ for example in a 750mL solution - how many mL will you need to create the 1 mg/mL concentration of quantity of 500mg chemical X? 

Is it just 19.5% more of the 500mL volume or do you have to figure out the molarity of each and then go from there?
Knowing that the material (solute)  has a solubility of 1 mg/ml in 95% ethanol does not help you predict its solubility in 75% ethanol. It could be more soluble or less soluble, depending on the properties of the solute.