Pretty cool bosses! I've been thinking of going to 2.5" tires on one of my MTBs, would be nice to have 'em like that.

I've rolled cartridge type pads out of their holders before.

But, in general a little forceful encouragement doesn't hurt. The things are designed to stop you after all.

Thanks. But the location width wise is a factor mostly dependent on the rim width and arm/pad specs. I've seen set ups where with great boss position and no pad interference the tire still snags on the arm's at the boss. If you're figuring this out yourself a mock up is highly suggested. Andy.

The long arm, having the much higher leverage, the V brake pad to rim distance may need be quite small ,

so that may keep the noodle from releasing..

Mini-V shorter arms, less cable pull / MA this is less of an issue..

As braking force tends to push the posts apart, and those posts being lengthened,
adding a booster arch on the end over the brake, would seem advisable.

Yea Cyclocross race mechanics cut down long-tail pads, in the past, but now you just buy them as such..

As the base of my extended bosses is a larger diameter then the OEM base size I think the flex in the bas will be less then the OEM speced bases. So the portion of the canti boss that the arm slides onto being the same in both cases will have the same flex, in both cases. No additional flex with the extended base bosses. (and actually my feel suggests that my extended base bosses actually flex less then the OEM ones do). But adding a booster arch is always a good idea and can often reduce the squeal that some brakes have. I have wondered why booster plates haven't been more common sometimes. Andy.