NO you don't have to run Test at the same dose with your Deca.. in fact all this does is increases the the potential for negative side effects. This is an old way of thinking that to prevent "deca dick" to always keep your test at least as high as your deca. but fact is as long as you have enough Test to sexual function (generally 150mg per week) then thats all you need.
I've ran over 1500mgs of nandrolone with only 250mg of test. no issues. in fact if I would have follow Dylan's advice and ran just as much Test as I did the nandrolone then I'd of had way more negative sides.
anyhow. thats just a rant

OP, nothing wrong with 300mg test 300mg deca. the dose is low enough that it won't matter if they are equal or not. running Mast with nandrolone is one of my Favs and highly recommended. but, you don't have to do everything on cycle 2 brother. theres always time. this is a marathon not a sprint