Oddly, I am in the opposite situation (My house was built in 1943). New 200V breaker box, old wiring (2 different ages!). How much did your wiring cost you, and did you do it yourself?

My understanding is that either solution you are considering is good. The electrician I used even told me I could put my old breaker box on the other side of the house to do what you suggested, but the only real advantage is shortening some of the wiring runs. Would love some other opinions on this.