I have no idea how close your bodies internal “panic” meter is adjusted to the real world capability of you 853. But I'd advise you to heed it.
However there are some things you can do to prevent tipping.
1) keep the heavy end up hill.
Which means, no load in the bucket you reverse to go up a steep slope. But if the bucket is loaded you drive forward up the hill. Because any skidsteer, and especiallya 853 have such a short wheelbase the operator needs to pay close attention to the slope of the jobsite.
2 Avoid driving on a side hill, when ever possible. This requires experience and sound understanding of limitations
3 Always carry the load from A to B as low as possible, then if the machine tips forward it will only tip until the load touches the ground.
When lifting heavy loads high to say place on a truck, park the truck in a level area, or AVOID parking the truck where there is a downhill slope towards the truck, if anything you want the slope up hill towards the truck in this senario. Driving forward,down a slope, with a heavy load, high in the air and trying to stop at the bottom is 5 point invitation for trouble.
The operator must understand how to keep the machine balanced, if you work with these tips in mind, I think you will become comfortable in the seat, If you don't, perhaps a skidsteer is not for you. Also a 853 has a short wheelbase for its lift capacity whick makes it more prone to tipping then some other machines that are a few inches longer. Further, reducing the weight your lifting or adding counter weights can help.
Hope this is helpful