balancing with new conrods

[RDfella]

Would appreciate some input from members here before I start drilling.
Am now ready for crank balancing and so spent this afternoon weighing components and calculating what mass I need to apply to the journals before drilling (if necessary). Actually, I shall be under-balancing and compensating with tapped holes that can accept balance plugs to alter the factor in situ, but let's not compound the issue ....
I was steadily working though figures when I found two things: first, the calculations from a member that I'd logged for reference contained mathematical and other errors, so was forced to disregard that. Then, on checking and double-checking my figures, I was/am concerned that they are so far from factory ones. I appreciate that Thunder rods are noticeably heavier, but, as per my opening line, I'd like someone to review my calculations in case I've gone astray somewhere. Don't want to find out I'm wrong after drilling ......
Rather that try to lay things out here, I've put the measurements / calculations as an attachment.
Thanks in advance for any comments.
     

[RDfella]

I see as of present my calculations have been downloaded 34 times - but no confirmation or correction comments.
I drilled / tapped for the removable balance weights this afternoon and will be drilling (assuming it's necessary) for the balance factor base figure tomorrow.

As a side comment, have to say - as others have remarked - that the Thunder rods are indeed a work of art. But not without a few shortcomings if put to use. In my view the BSA rods were a better design. If only someone had decided to make a die so new ones could be forged (always better than machining from billet). With a change to a steel cap that would have been spot-on (at least as far as alloy rods with their fatigue issues are concerned). 

[muskrat]

G'day RD.
Figures look good to me.
How do you intend to add the weight to the journals?
I cut strips of lead (gutter flashing) and wind them around the journals.
Cheers

[Colsbeeza]

Hi RD, Do you intend to followup with dynamic balancing?
Col

[RDfella]

Thanks for that Musky. Exactly what I do. To measure imbalance, I stick another strip where required to achieve balance and then remove an amount of steel equal to that weight from an opposite point.
Col - dynamic would be nice, but postage would be quite stiff, and then there's the delay - probably a month or more. Pity, as that would smooth things even better.

[Greybeard]

I know nuffink about the subject. I downloaded the PDF out of curiosity. 🤐