I used studs with jam nuts on the back side and lug nuts on my 149

https://www.mcmaster.com/
94846A520 jam nuts
98750A474 Studs
4991T964 lug nuts

just a few items to consider.
your wheels are called stud piloted wheels.
Stud Piloted means the wheel is centered on the hub by the conical (or spherical) shape of the studs' seating surface. ( this same term applies to hubs with studs engaging with a cone/spherical seat in the nut.)
the wheels are self centering once the proper lug stud or lug nut is tightened.
the issue you will have is the cone/sphere for a given thread has a smaller starting diameter than on the same size nut. stud cone ID starts at the thread minor diameter and the nut has to start at the threads major diameter.
A nut's conical seating surface is too large for seat intended for a stud of the same thread.

the CC steel wheel is designed for a stud with a cone and has a raised area to accommodate the conical shape without bottoming out against the hub. if you simply drill the hole larger you will likely loose that seating surface and you run a risk of the nut bottoming out against the hub before the wheel is fully engaged. basically you cant tighten the nut anymore and the wheel is still loose on the hub.
Steel stud piloted wheels either need to be very thick in the web area (like a semi wheel) or they have this stamped raised seating area like most car and trailer steel wheels.

now these are not high speed applications so a little out of roundness is not gonna mean much to you. but you do need them to be tight so I would not drill them out. there is not a lot of weight on these wheels or a lot of torque. you could just use the nuts and accept they are not really centering the wheel on the hub.
you could find some wheels with negative off set and mount them backwards, the back side of the wheel will have a larger cone shape then the front side and it will likely match the nut better.
use jam nuts, or - go back to the lug stud.