You can now close your SP map since you won't be needing it anymore.
Now open up the HLMT tag and double click objects/characters/hunter/hunter. Now, in the left pane, click where it says "IFP Plugin - "hlmt" - Edit Mode". It should now say dev mode. Under reflexives, click Variations. Now click all dependencies in the next pane. You should see something like:
Unknown | udlg | sound\dialog\combat\hunter |
Double click sound\dialog\combat\hunter and change it to Nulled Out.
Now go to the WEAP tag and select hunter_particles_cannon\objects\characters\hunter\hunter_particles_cannon. Click on all dependencies and look near the bottom for the HUD row. Double click where it says nulled out and select a weapon's HUD to use as your aimer. (Ex: if you use shotgun, you'll get the circle in the middle of your screen, etc.) Under reflexives, select attachments. Change sound\weapons\hunter_cannon\hunter_cannon_loop\hunter_cannon_loop to Nulled Out.
Now go to the ITMC tag and choose a weapon to replace. This is where your hunter's fuel rod gun will spawn. Select a weapon and go to item permutations, then under that, click visible dependencies. Change the weapon to objects\characters\hunter\hunter_particle_cannon\hunter_particle_cannon.
Now for the final step. Go to the BIPD tag and select either masterchief_mp the elite (which ever you want to be the hunter). Go to visible dependencies and change the hlmt (should be the top row) to objects\characters\hunter\hunter.
A few notes: You can change the hunter's jump hieght and speed that same way you would change it for a normal character. The hunter will have shields, but you can always turn those off.

I've only found one bug by doing this. If you try spawning with a normal weapon, you'll have to go walk over where the item you replaced would normally be. Your hunter won't do the animation you for meleeing, even though he is, unless you spawn with the weapon your replaced, but then you can't shoot until you walk over that spot. It really depends what you want. You can follow one of the other tutorials for playing as a hunter, but you won't have an HUD, or you can just deal with the fact that an animation doesn't show.