I don't have a problem with spraying or having to line anything up. But, I do have to make sure the tube is empty after.
Like I said I've had a PA for decades and chastity cages about 1/2 that time and mostof that 24/7 I almost always carry a couple of flattened cardboard toilet roll tubes. Ideal if you need to stand to piss and prefer your spray confined to a stream.... well at least not all over your trousers and boots. They are free a steady supply and if ditched outside they will degrade.
I agree, the Bon4M is very comfortable but due to the more open design I have no problems with peeing. For sure, I am sitting but to pee in a stealheart is much more complicated. Carefully rinsing is the solution.
I've got a screwin urethal tube from one of my early cages . Fits nicely in my pocket and is always with me. It's stainless steel and just requires rinsing of now and then