Focus -
get the camera set-up, adjust angles then manual focus somewhere in the middle of the field
since what is off-camera never really matters, but can aid in the shot ....what I mean by "adjust angles" is to adjust the subjects angle - to be inline with the lens angle & the focus plane of the camera
most anything can be used to manipulate the subjects angle, from hobbyist vises, to vise grips, to kneaded putty, to stacks of wood / coins / plastic ...or even hanging from above
then use "sharpening" in the last steps of processing (usually no more than 25%)