Can't help, but will say this - buy the very best quality that you can afford. The actual cost of the ply compared to epoxy and paint and the rest means that it will be only a very minor increase in overall price.
Also, it is best to buy ply that complies and says that it complies with a domestic set of standards - a lot of inferior ply is marketed as BS 1088 but because it is not sold in the UK that doesn't mean anything. Only domestic standards are enforceable against the manufacturer or distributer.
If it were done when 'tis done, then 'twere well it were done quickly