[Harp-L] Which Hohner Rocket Low-Key harp to buy first?

[Opus314 .]

I just saw a cool video by Greg Ranger on the Facebook Harmonica Facebook
Group.

"Trying a little Dennis Gruenlings You Can Do No Wrong"

https://www.facebook.com/groups/HarmonicaJam/permalink/1337338202995668/

I think he is playing a Hohner Rocket and it says in the comments he is
playing a Low-D.

Way back I saw Adam Gussow interviewing another player on the street
and that guy was playing a diatonic with some extra holes on the bottom so
he got the low notes that way.

1 - Which diatonic has the extra holes on the low end?
2 - Is it or the 10-hole Hohner Rocket the better choice?
3 - What key should I buy first when buying either

Thanks for any help.