I don't want to get us into a one-upmanship competition, I spent all day with a D6H on a 40-degree sideslope, occasionally steepening to 45 degree (1 in 1) and to be honest, the first half-hour was underwear-changing territory. The low point was my dinner-bag falling out of the cab door, leaving a trail of sandwiches all the way to the bottom. This was on dry clay, I wouldn't have attempted it on topsoil or anything loose. As it was a couple of times the top track spun.
In a later life, I was trialling a dozer with a prototype engine for a well-known manufacturer and was instructed to see if I could make the engine lose oil pressure while pushing. This involved max side-slopes which again was 1 in 1 due to soil conditions, 1 in 1 uphill, (I could have moved more with a wheel barrow) and just over 50 degrees downhill, which resulted in a footprint on the roof-lining. My rule of thumb is your backside always thinks the machine is 10 degrees steeper than it really is.