Basically, this is the question: I can use the olives and connector inserts proper for Avid in a Shimano Deore M596 brake/hose? Has anyone tried and can report if it worked perfectly or if there was any problem? Thank you very much.
No you cannot. They are not cross compatible. Shimano Olives, hose and inserts only work with Shimano components. The same is true for Avid brake equipment.
Beyond not being designed to work together you void any warranty claim by not using compatible equipment. You also give up any legal approach to the manufacturer if you use other company's parts. So if you crash because the brakes failed and want to say that's Shimano's fault and it actually was. They will say it had Avid olives and inserts on it.
When i look in my catalogue at aftermarket hoses and connectors (perhaps from Elvedes), the main factor with olive and barb compatibility is mostly relating to the hose, in instances where the compression nut is basically the same size.
So to avoid problems, you use the olive and barb suitable for the hose you wish to use. Where you are certain the outer diameter and the inner diameter match your olive and barb, the likelyhood is that you can get a good seal. The main concern is that you will get a leak when testing straight away and have wasted time and money on the "wrong" parts. If the hose is held fast by the olive it is unlikely to fail catastrophically and unexpectedly after not doing that when you sqeeze hard looking for leaks. I hope you see what you mean there.
My opinion is that it isn't worth doing unless the parts you need are totally unavailable because you waste all the time fitting up and bleeding, and all the money on fittings if it doesn't work perfectly. It's a gamble that most people can't be bothered with!
I have got a lot of shimano pins and olives here and now i switched to sram/avid HRD (Hydro road) - the prices for these olives/hoses/sets are ridicilous. So I had good look at both. shimano (brass-) olive and (stainless-) pin should work absolutely fine on sram/avid hoses. The cone of the housing/screw that actually presses the Olive onto the hose are the same (Diameter of the hose also). This only accounts for the standard (silver aluminium - black pin) avid/sram hose olive. These Red ones "stelamajjig" or whatever (i only know of etap road) - i have these here - are a bit different but i don t have the corresponding etap levers. Somwhere someone wrote that these may press a valve when mounted - with the standard ones these valves would stay closed. regards from berlin