from my humble expeirnce at barrows (over 60m worth drops + a ton from runes), i say 6 is the best. my longest dry steak is like 15 runs. + i don't even use prayer pots so i can rake huge ammounts of money from it. get 6 and stay at 6.
i would only use them for 1 thing: con the prices of gold leafs magic stones and marble are totaly way out there. i'd get free of those and give them around. also it would be fun to see the lowest level possible to do dt and fight caves. but drop the cape after. also keep it apart from my main.
i rarly post here, but i'm very intersted in going to kill the kings. i'm only 92 cb but i'm 94 range (95 soon maybe). of course i'd range and i have some expirinc at the kings. please pm in game. rsn: shadowkill7 or i_l_il__il_l