I agree with mulligan.

Two things - typically V tails are about 100 degrees spread, sometimes more, sometimes less. 90 will work.

Area should be about the same as the equivalent conventional tail (tailplane (stab) + fin ) combined.

There is evidence that V tails are bad at exiting spins as one of the surfaces gets blanketed.

I guess for the size and weight of a park flier this is not a consideration.

You are also meant to save drag with a v-tail - less interference drag and one less vortex than a conventional, though in practice I doubt it makes much of a difference particularly for the type of model you are making.

Speed 400 electric? well I'm no expert on electric flight, but I'd guess with that battery and motor combination you should be building around the 18-24 ounces mark with a wing area of 300-400 sq inches. Maybe a bigger wing area considering you are opting for a wing planform which has been designed for supersonic flight!!! (and will therefore be inefficient at the low speeds your plane will be flying). My guess is your flights will be radically shortened because of the drag produced by your wing planform.

For a first model, I would recommend you choose a wing shape less radical than that - you could always stick with the jet styling idea, just not a supersonic one...