Circles Along an Arc

I'm trying to create a 2D model for a part to be cut by CNC tools (water jet) and I need to evenly distribute a number of holes along an arc.   I've got the arc, and I can manually calculate the positions on the arc of the various holes but it will be a bunch of work - particularly given that I'm likely to need to tweak the design a number of times.  

In short - I want to place say a total of 15 circles (holes) - each 3/8" diameter along a 90 degree circular arc with a radius of 5" starting at 0 degrees and ending at 90 degrees - equally distributing the circles along the arc. I'll be doing this twice (total of 30 holes on two arcs in the tool path) - and the finer the grain of adjustment the better - so "lots of holes" and calculating the coordinates for the center of each hole (and repeating as the design changes) will be a serious pain.

Is there a way of doing this that is simpler than manually centering each of the small circles at the coordinates calculated for it's center?   I don't expect that there is a function that lets me do this in a totally automated way - but if there is something that lets me say "position the next circle at arclength X" or "position the next circle X degrees from the start of the arc" that would be wonderful.  

I can shrink the radius of the arc by the radius of the circles and create circles in a manner tangential to the arc - but this still does not help me with the equidistant distribution of the circles along the arc.  

If I stick with 15 holes they'll need to be 6.429 degrees apart - or 0.561" apart along the arc (arc length).

Thoughts?

TIA

OK - I found this thread - that I think is going to help...  https://forum.librecad.org/Making-arrays-td5717934.html

I think I'm going to be able to make this work.  

1, draw one circle on the arc;
2, use Modify> Rotate, specify rotation angle and number of copies.

Thanks - working that angle.   I'm getting some weird results - but think I'm headed in the right direction.