Just looking for opinions on this random question

[EsperMagic]

So if Horse Master allows a cavaliers mount to stay equal to his character level, would it apply to a single dog from the Huntmaster archetype as well? Or say each time you take it apply it to a dog?

Also can you stack multiple boon companions as long as you dont exceed your level?

[Twisteminds]

All that feat seems to be good for is multiclassing.
It has no big effect on the dogs unless you plan on abandoning cavalier at level 4. You are really just dividing your total HD allowed amongst many smaller creatures. You will still only have so many HD to use, even with that feat.
4 levels in cavalier and 2 is something else still means you only count at level 6 when talking about your animal companion. You only have 6HD to spread about your various animals.
Without the feat you would have 4HD to spend.
1 dog at 6HD with the feat or 1 at 4HD without
6 at 1HD each with the feat or 4 at 1HD without.

[EsperMagic]

ah got it, so boon companion is the only choice.