I think your math is off a bit.
Distance across=32LY Therefore 10000 ring * 32 LY/ring = 32000 LY
A moderate WHG 50 on a frigate with Nav Optimization X + Nav officer + VIP = 318Fuel/16LY jump. 320000LY * 318 Fuel / 16LY = 6,360,000 fuel one way. With VIP 1 Diamond = 58 fuel. Therefore you'd need to carry 6360000fuel/(58 fuel/diamond)= 109655 diamonds (which if purchased at Sol would be a mere $230millon solars - a pittance given the epic nature of this quest). You have 7 cargo slots on a frigate (after the necessary WHG slot). You'd therefore need to build out 7 fairly modest ACB 210's to carry all the diamonds you'd need.
Each 16LY jump with the above takes 15 minutes. You'd need to do 320000 LY/16LY/jump = 20000 jumps. At 15min/jump * 20000jumps = 300000minutes = 208 days (assuming you jumped immediately after the timer finished.) Of course you'd abandon the ship - it would take 2x the fuel and 2x the time to bring it back again.
That is the lowbie way to do it. Alternately you could have your frigate with 4xWHG 500's which would dramatically increase the diamond cost and ACB mark required for huge decrease in the total time it takes to do the trip.
Good thing I not a math teacher..
But still around a year..