That looks doable to me but you are right- you will eventually need a full cap. A few suggestions:

- I would draw the ventilation direction on your template so they have something to refer to when working on the temples

- Keep the density low

- The cut is everything in a situation like this. There are a few different tricks to get it to look its best but it is all in crafting a style that downplays the thinning areas of your own hair

- Concealers can be messy and a pain to deal with but a touch of Dermmatch or Couvre would help tremendously with your sides being thin

Can't wait to see it when you get it all sorted!