Only realised the name says greaters, but the article says lessers. If the endeavor is really greaters, then my only recommendation is the dungeon in brimhaven. It is possible to OSRS gold use some of the aforementioned options, though you need to contend with all the terror dogs too. Regrettably, there aren't a number of great options for greaters (no pun intended), however, you just have to soldier on whether it's these.
Inventory: Range gear for Ahrim (such as rune xbow). Uncomplicated teleport to an altar (Ardy Cloak, House teleport). Law and Blood Runes for Kharyll teleport (unless using house teleport with Kharyll portal). Spade. 4 Prayer Potions. Monkfish.
Strategy: Go to Karil first. Pray attack hindsight, power prayers, and protect from range, and hit him with your special attacks. Finish him off with your ice spell. Run out. Proceed to Ahrim. You should still have almost 30 prayer points. Switch to range equipment, plead magic (and buff eye if you have it). Run out if he's dead. Proceed into Dharok next. At this point, you should have about 1-5 prayer points left. Pray melee for his very first hit, hit him once with ice hockey blitz, and measure away. You can usually get in 5 hits; he'll start moving on the fifth strike, which means you should be far from him if you would like to become in 5, otherwise only hit him 4 times and hide behind his grave. After a few moments, run to some corner from him and hit him again before he reaches you, and replicate. Finish him in this manner.
Take on the remaining 3 brothers in exactly the identical fashion you did Dharok in any sequence you choose. Things to do to the tunnels: Determined by which brother you make it in the tunnels, set your quick prayers to the correct protection. When he looks, don't panic (you'll survive the first few strikes ), prayer pot quickly, and reach quick prayers. Finish him. The thing that will consume most of your meals is your tunnels, so understand the design and cheap RS gold get to the torso as fast as possible. When you reach the puzzle, if you're not exceptionally fast, take 1 step back from it, hit the monster attacking you with an ice spell, and you've got 10/15 seconds to perform it.