Can you share the brand and model information of your robot?
the only reason one would do that is to preload A1 to minimize backlash. when doing so, tilt up to 10deg is used. on a larger robot tilt could be smaller since the bigger robots are heavier.
but you went the other way and decided to take a giant robot, tilt it by 30deg and you are surprised with results? and then manufacturer tells you to not do that but you still want to do it? sooo.... since you are ignoring advice and already made your mind, what is there to discuss?
perhaps try defining what backlash etc is acceptable for the process you work with. then try selecting robot that meets that (if possible). maybe it exists but...
i don't think i have seen robot tilted 30deg before.
and don't think i have seen tilted any robot rated over 120 kg and you are 5-6 times over that.
