Icon IC 743 piston weight incorrect

Those con rod numbers all make sense, so your scale looks to be accurate.

Well, with the bobweight going up around 80+ grams, you sure will be out of balance. Options:

• Add more external weight, but may not be possible to add enough up at the damper. Then again, if some was drilled out of the damper ring, you might get there.
  
• Add heavy metal to crank throws
• Change to SCAT rods which are going to move your bobweight to around 150 grams UNDER stock. That ought to balance out with 1 not-too-deep hole in each end crank throw (based on past experience). With SCAT rods (and Eagles too), they are weight matched in sets, for total weight as well as big and small end weights; the end weights come with the set documentation for the SCATS (and I am pretty sure for the Eagles too). So for a 'very good' balance job (better than with the stock rods), you don't have to work over the rods. You just need to compute up the new bobweight (not hard as you seem to be able to work with numbers, or I can help show you how), and have the shop balance the crank to that bobweight with just your crank and external weight parts. A lot less pricey that way.
  
• Change the piston plan but IDK what you will get that is lighter. Even the KB hypers weigh in the same range as what you have. (And they are advertised to not fit in the stock Magnum head chamber anyway....)