As a WAG... How much time should I allow a typical TF professional to design and draw plans.

I am 2-3 years from starting cutting on a TF addition to our stick built home.

I will be using mainly Alaska Yellow Cedar, and some western Hemlock. While I think the actual cutting and erection may be within my capability, designing and engineering are something I don't feel adequate enough for. Especially with the wind and snow load I will need to build for here (SE Alaska).

By the way there are NO building requirements except the ones I choose! I am remote.