At 80K no Montana deck is beyond you.

As for a half

Mona
Spag
Ace or Prince Jr (whichever you prefer)
Edd Cr (Or Desmond if you don't want to fork out 40K ish)

For higher Stars

I go with Don as my 5* in a half deck for Montana

Almost every clan is viable in elo. go look at public presets for decent elo decks. the deck im currently using is

http://www.urban-rivals.com/en/presets/?id_preset=2495460

My advice: Stick with mono-Piranas

+1 to both of the above.

imho a good rule of thumb is to mix up atk manip/SOB/Vortex with power manip/damage manip/SOA so that you can bluff the low pill battles (atk manip/sob) as well as win the high pill battles with power manip or damage card

Don is cheap and packs a punch for his price, but he's somewhat similar to XU82 - better for low pill battles. I like Don, but somehow nowadays i tend to lean towards using Jimmy. Tino is also useful if you like bluffing low pill battles and still packs a punch either way.

imho if you want even more flexibility, going for lower -atk clans such as Uppers or sakhrom is also good.
Hefty/Herman Maurice Jose Star/Wendel/Samantha is pretty cheap and provides decent utility.
Dobbs Ld/Anakrohm Wakai/Murray Lakit/Jautya Stella/Miss Stella could also work.

Jungo and Freaks can also work in combination with most clans since their cards have a diverse range of utility and are on average pretty good base-stats wise meaning they can go for high pill battles quite easily

Piranas 2s are actually kind of outdated. For example, Tula is great vs some attack manip clans, but she gets eaten by ability attack manip, ability SoA, Prot: Power, Prot: Bonus/Stop Bonus/Copy Opp Bonus on attack or power manip clans. That's a long list...

I would recommend using Selma/Lizbeth, Raeth, Ector, and Hawkins for an offensive Piranas half. Combine with any 11-star half that has good utility (like Pegh, Jean, Rodney, and Benicio) for a very solid deck.

Pegh, Jean, Rodney and Benico aren't all that strong. I would go with Diana, Clover, Lucy and Wanda

I like to experiment with Piranas, I used mono Piranas for some time and like you I felt the need to try half decks.

This is my deck, it doesnt have nukes, i prefer to win by strategy to win 3 rounds or otherwise just neutralize the big threats in their decks.

Im not a top player my maximum was 1322 but here is my deck, hope at least you have some ideas to build your own.

http://www.urban-rivals.com/presets/?id_preset=2494776

@ComeAtMe:

I think that sounds like a great half to run with Piranas, too.