I used this bender to make my own 5/8" aluminum crossover vent tube to replace the rusty stock one. I'll post pictures later.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
It has a pretty tight 2 1/4" bend radius and worked well on some annealed aluminum tube from Summit:
https://www.summitracing.com/parts/SUM-G2558
I'd be surprised if it worked well on stainless tube. Stainless is so much more difficult to bend. I have no plans to make anything out of 5/8" stainless tube with it, but if someone has some scrap they'd like to send me, I'd be happy to try bending it and report back. Ridgid makes a ratcheting bender for 5/8" with a 3" radius of bend - might work better.
The problem you'll run into with the hardlines is you will never get close to the bend radius you can get out of a 90-degree hose fitting. You have to have the tube sleeve pre-installed on the tube before you bend it (otherwise the sleeve will not slide through the bend), which means you have to flare it before you bend it. So you end up with about a 1.5" straight section after your flare before the bend starts. The bend radius of those hose fittings is probably less than 1 inch. It might work for you - just a consideration to keep in mind.
Another issue is while the bender makes a smooth bend in the aluminum tubing, it does collapse it slightly in the bend (not as bad as a compression-bent exhaust tube, but not nearly as good as mandrel-bent). I don't know if a slightly collapsed -12 tube would restrict oil flow too much or not. Probably not, but worth thinking about.
The best solution is probably Chad's - sleeving and heat shield.