So I have a 3* redox mech and a 3* stalker mech and both need like 1875 acoins for ranking up. I'm confused on whom to rank up

4* redox will give 20 emergy cap 4* stalker will give 16 energy cap

4* redox will deal more damage with ability while having more hp 4* stalker will have more hp so it won't be squishy https://100001.onl/

I think 4* redox would be a better choice, BUT I want to put helix racks on stalker and try it out. I only have helix rank 8,10,16 and rn I'm using jav racks 6 on both arms

So give me some advice pls.