Consider a Williams barrel mounted peep sight. Might have to flatten the bottom a bit or drill a stepped hole/file the aluminum base holes to matchup to your T/C drilled/tapped holes, but it is a simple task.

https://www.amazon.com/Williams-WGR...p;pf_rd_r=BH4F7PX5P8MQ87CD7N8A&psc=1

If you are able to file a dovetail slot in your barrel, the Marbles Bullseye sight is another option. This is the fixed rear peep version. Height adjustment would be by finding the proper front sight, and filing it down ( to raise point of impact). Windage is be drifting rear sight as needed. You can cut off the outer ring if you think it is too high. Pretty simple and robust solution ( and low cost) for you, if you can make a dovetail slot. Marbles also makes a version with an elevator slide. Still needs a dovetail.

https://www.midwayusa.com/product/100589347?pid=679676

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