Is it okay OSRS GP if I do not use pots or pray on non levelled stuff? And, if I receive a multi combat task, should I use prayer, pots, and cannon? A friend of mine said that I wanted 55 crafting to make the slayer helm, even when I use points to understand how to make it. Is that accurate? Can Verac's armor be some good? It's high defence stats, and also a good prayer bonus. Additionally, cloaks provide a prayer bonus of 3. Should I substitute one for my own skillcape?

It's ok to skip out on the prayer but it won't be too fast. Everyone's giving you guidance for the quickest, most effective slaying... cutting corners will result in it being even on lower leveled stuff. But hey, whatever suits you... well in the event that you get like desert lizards or something Turael-tier then yeah you should be OK. But you are definitely not going to him.

Using full verac is just going to be in repair costs. Not really worth it, also less prayer compared to using a proselyte platebody. Yes, black mask is ok. Infact, you SHOULD be wearing it unless you get an undead mission, in which case proceed with the salve amulet and whatever helmet you want. One more thing, you definitely should utilize a cannon whenever possible. Even in single battle areas it is possible to conceal places so that the cannon can attack everything in the area regardless.

Also I'm again going to suggest the Brackish Blade, unless the 500k for it's too much after all of the other stuff. Many monsters you get while slaying are feeble to stab, and Brackish Blade is equal to some Dragon Scimitar except at stab instead of slash. It's an aggressive stab too so you can indeed train strength. Really do indicate piety. It is buy RuneScape gold amazing. Get 70 prayer as soon as you have the money to do so. Also super sets are great.