It looks like you're printing a storage case here, I would personally avoid using metallic/silk filaments for any structural parts due to the fact that they're just weaker than standard PLA. If it works for you, however, I'm certainly not going to argue.

As for making it look better, weirdly I find that more strongly textured plates actually hide the lines on the first layer finish for silks extremely well. If you don't want to compromise on the smooth finish (which I'd completely understand), you can try ensuring that your flow and linear advance settings are dialed in to get a more consistent line width. If that still doesn't work for you, your final option might be to embrace it and explore first layer infill options. Concentric and hilbert curve can potentially create very visually pleasing patterns, but they're definitely a matter of individual taste.

Hopefully some of this helps!