there are a few values published by developer, "http://www.prode.com/en/hydrate.htm" I have verified some of these points (ask Prode for the list), with simplified model for hydrate formation pressure you may expect an error in the range 3-15% (depending from structure and temperature), errors in hydrate formation temperature are in the range 1-2 K the complex model is more accurate, when adding methanol as inhibitor erros are about the same (with the specific parameters provided for CPA PR Cubic Plus Association or other models, however I suggest to contact Prode for more accurate figures...
Hydrate formation curve in Excel Prode Properties 1.19 includes a utility which allows to calculate the hydrate formation curve directly in Microsoft Excel, the distribution files include a Excel page hydrate.xls , from this page one can define composition including all common hydrate formers C1 Methane, C2 Ethane, C3 Propane, C4 n Butane C4 i Butane N2 Nitrogen CO2 Carbon Dioxide H2S Hydrogen Sulfide plus inhibitors as Methanol, Ethanol, Glycol and salts (salts require the electrolyte package) Hydrates modeled according van der Waals and Plateeuw (rigorous, statistical approach) and Cubic Plus Association (CPA) for vapor, liquid phases A free students version is available from Prode WEB Site