Rebuilding wheel from 27.5 to 29"

I'm wanting to rebuild a 27.5" DT Swiss M1700 wheel to a 29".

From what I understand I will need a replacement wheel, rim tape and the correct length spokes. I should be able to reuse the nipples.

Using the calculator for an XM481, DT350 hub in boost CL, I get recommended lengths of 303 and 304mm. I can't get 303 so I'll go 304.

My question is how do I know whether to go with 2.0/1.8 or 1.8/1.6 DT Champion spokes? I'd like to keep the same gauge so I can reuse the nipples.