Perform your swings at the top of every minute. Start at 3x2,4,6. Add another series next week so it's 4x2,4,6. Build up to 8x2,4,6. Then build up to 8x2,4,6,8. Then 8x2,4,6,8,10. Upgrade to a heavier bell at this point.
If a heavier bell is not an option and you want to emphasize strenth, progress to 8x4,6,8,10,10. Then 8x6,8,10,10,10. 8x8,10,10,10,10,10. Finally 40x10.
Or you wish to emhasize more conditioning with this weight, try using the original progression with a higher multiple. First 8x3,6,9,12,15. Then 8x4,8,12,16,20. Do this all the way up to 7,14,21,28,35. I would highly recommend moving up to a heavier bell. But if it's not an option, implement the option outlined in the above paragraph. 8x14,21,28,35,35. 8x21,28,35,35,35. 8x28,35,35,35,35. If you don't have access to a heavier bell after 40x35, I'd suggest you find a better job.
But this is just my idea. I'm not an expert or a professional. If someone comes along who knows better, Id listen to them.