What would you fit to your Leopard 1?

I am close to reaching  9,000 bonds tp upgrade is my Leopard 1, Tier X German  Medium Tank. However I am a bit at a loss on what to get with the bonds. I already have Innovative Loading on it and I will definitely get the Improved Vents on it, but I do not know if I should get the improved Vertical Stabiliser or the Improved Coated Optics.

My crew is all 92% on the 4th skill, except my commander who is 27% on her 5th skill. (Recon and Sit awareness are completed). Once the rest of the crew finish the 4th  skill, Brothers in Arms will be done for everyone.
 
View range without coated optics is 443 m already. With, it goes up to 487 m. If I put the Experimental Optics, it would go up to 521 m.
 
What should I get from the bond store? Stabilizer or Optics? Or something else?
 
Thanks in advance!

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