No offence to you but for the love of ICE - DO some research, and don't rely on forums !
You get one shot at doing this right.
😂
You'll have to decide what's best because you'll get conflicting info from well intentioned people.
I rebuilt my engine at home 3-4 years ago, and had to break\run it in on the road, whereas 350Butcher had it on an engine dyno (not chassis).
This is what I followed, listened to and did - is it correct/perfect - too late now 😆
https://dsportmag.com/the-tech/education/quick-tech-performance-engine-break-in-the-right-way/
https://www.youtube.com/watch?v=-yRudUHeSng
(3 parts)
I really like Lakespeed Jr, so have a search for him on YT (works with Total Seal piston rings now), huge amount of knowledge and very humble speaking to others:
https://www.youtube.com/watch?v=kJw1_levGew
I used:
Millers Oils CRO 10w-40 Competition Running In Mineral Engine Oil (call Opie Oils and see if they can help needs be).
Oil viscosity (running in, and after) depends on your build and clearances on the bearings (don't assume stock is correct).
After running in, drop the oil and carefully open up the oil filter and inspect it.
You'll likely see swarf, so ensure that you have enough of your normal oil and filters to run it and drop it again to help flush it out, repeat as required, it will bugger off eventually.
It's totally down to you how long you run it and drop it again (I verged on the paranoia side of things). It's one thing I didn't see many industry people talking about much.
I use this for cutting the filter:
https://www.amazon.co.uk/gp/product/B09J2M1WVX/?th=1
Good luck 🙌