I want to be able to adjust the position of the grid tick labels to be inside the map boundary. Setting the gridliner xpadding works to move the labels away from the map, but setting the xpadding to a negative number results in hidden labels. I found that that non-inline labels that overlap the map boundary are hidden by default, so I experimented with setting the visibility of all labels to true. However, that resulted in the labels appearing at a 45-degree angle.

I'm essentially trying to do something like this. Note: I am not looking to use the inline labels option, since (at least to my knowledge) there isn't a way to fix their positions to a particular x or y offset from the map boundaries. Changing the xpadding doesn't have any effect with the inline labels. Maybe this should be an option instead?

Example code:

import matplotlib.pyplot as plt
import cartopy.crs as ccrs

plt.figure(figsize=(12,9))
ax = plt.axes(projection=ccrs.Miller())
ax.set_extent([-130,-65,20,55], crs=ccrs.PlateCarree())
ax.coastlines(resolution='50m')
gl = ax.gridlines(draw_labels=True, color='gray', linestyle='--')
gl.top_labels, gl.right_labels = False, False
gl.xlabel_style, gl.ylabel_style = {'weight': 'bold'}, {'weight': 'bold'}
#gl.xpadding = -10     # Ideally, this would move labels inside the map, but results in hidden labels

No xpadding:

xpadding set to -10 and visibility hard-coded to True results in rotated labels: