I've already transplanted the front of my scalp. Can I use a different doctor for the rear of my scalp?

Question in the title.

For reference, I'm a diffuse thinner who recently had 2,700 grafts done on the front of my scalp. I went to Thailand for this about 4 months ago. I had verteporfin injected to help regrow the donor area.

Now I want to do the rear of my scalp.

1). Do hair transplants to the rear of the scalp require less skill than doing the front?

2). If I'm doing the front and rear separately, is still important to wait 9 months in between surgeries, even if it's a completely different area that's being transplanted, or can the interval between surgeries be shortened?

Thank you.