Changing type for each variadic template argument [on hold]

I have some class:

template<typename... Args>
class X
{
    using F = void(*)(Args...);
};

Now I want variadic parameters in F definition become converted with a specific condition:

template<typename T>
using custom_t = typename std::conditional<std::is_fundamental<Args>::value, T, T&&>::type;

using F = void(*)(custom_t<Args>...);

So, for example, for class X<int, MyCustomT> definition X::F should become void(*)(int, MyCustomT&&)

via Chebli Mohamed