finding suitable optimizer

Hello everyone,
I need help to choose the best optimizer in grasshopper for my case.
I want to optimize a high rise building structure ( modeled in Karamba ). This is a complicated code, and there are lots of variables ( near 2000!), I know it's a lot! :)) but I really can't change it! it's the only way I can achieve my goal.
The displacement is controlled to H/500 by use of Karamba cross-section tool. My fitness is to minimize the mass of the structure.
I used Galapagos, and after about 20 hours, the results were convergent. But there is a problem! I need to reinstate and save more than one results of optimization. Apparently, it is impossible. Saving just one result is possible in Galapagos, and because of numerous variables, it doesn't work for me to record all of them one by one!

I used opossum too. It is better for my case because it provides the possibility of revisiting all optimization results and saving them. But several iterations are needed for my case to achieve a precise result. I don't know why the optimization process didn't proceed after near 20 hours (iteration: 1147).

Do you have any suggestion for me? What is the best optimizer for my case?