Scania’s will hill hold 44t without a problem - the gatehouse at Stobarts in Stoke is at the top of a steep hill, tbh it was the only time I really ever used it.Generally, in normal proper use, yes... but still perfectly possible under the right conditions. Having boobs seems to be one of them...!
Depends on the engine, but probably a good idea to ease the brake up anyway.
Again, generally yes. A lot of remarks will insist that autos all have auto-holding abilities either built in or electronically effected, but I promise you a big heavy works vehicle carrying a heavy load is still quite capable of rolling back even with all the fancy gubbins. If in doubt, use the handbrake and avoid scaring the **** out of the ex-Gurkha on the security gate...!!
I still prefer the handbrake mind you!