Here's the specs I ran on my 98 380MXC. 50 pilot, 1.5 out on the airscrew, the stock slide, a 170 main, and an R1467N needle (most critical part) in the middle position. It's a Honda needle. The Keihin part number for this needle is DGH.
Seems odd to move up the pilot to a 50 but trust me, it works. This was at about 1000', stock exhaust, 40:1 Y2R with 92 pump premium. I went to a 175 main when I put an FMF pipe and TCII silencer on. I'm not sure what the elevation will do to the jetting but I'd still think this would be a good spec to start with, at least.
Setting the bike to barely idle helps get rid of the spooge, too. I had ZERO spooge with this setup on both exhaust systems.
This setting has been used and approved by several other 98/99/00 380 owners.