Use a Wii. Access to homebrew for loading/saving memory card files and checking your IGT is quite the boon, even if you plan to use Dolphin to practice.

Furthermore, in my limited but not unscientific testing, Gamecube tends to load much slower than Wii (for any%'s current route, this adds up to 15 or so seconds of IGT spent loading at a door).

Don't forget that playing on Wii removes some random crashes like the one when taking the elevator from Tallon Overworld to Chozo Ruins.

It's actually precisely because the Wii has such fast loads that crashes become negligible (especially entering Metroid Quarantine A with a changing beam, visor, etc. moreso when the turrets are alive). 

Though you can pause with Z or Start to reduce lag, the Wii will always have much less lag and take less time to load your beam or morph ball shell or whatever you happen to be waiting on. It's just that much better.

http://chozopedia.wikia.com/wiki/Gamecube_and_Wii_loading_discrepancies

Here's a page where I recorded a few samples of this idea that Wii is faster.

If you don't know which console to use...

E_Dragon

Skull64

AceZephyr

Metroid Prime

Frigate Escape - Inbounds

GameCube

KingØfRedLions

USA / NTSC

Normal

Hard

Difficulty

Metroid

Metroid Prime Category Extensions Leaderboard

Discord server

Video proof

Video proof/ USB Loader

Glitchless No Major Skips Category?

Metroid Prime Remastered

Dyceron

edzan

Superboss

just_the_most692

gdVertigo

chomsky

Metroid0925

UncleReggie

Nate09

Samuel6710

treadstone2121