Remember to only bother with dual duties if your strength and defence boosts are the same (or very close). If you have 125 strength and 20 defence, a dual duty won't do you a bit of good. And for a strictly 1-player set, I'd go with:
-Multi-use attacker
-Multi-use attacker
-Pure percentage defence (Downsize! -- everyone should have this. It -doesn't depend on defence boost.)
-Bomb
-Healer
-Freezer
-Shield (if you've trained defence) or reflector or one-use bomb or stealer
-Dual-duty (if you've trained defence) or another one-use bomb or even another multi-use attacker.
The cheapest good multi-use attackers over 6 icons right now are enchanted wooden bow, earth faerie slingshot, and stone club. All are buyable on the wiz (35k, 60k and 68k, respectively). The psellias fighting fan is better but more expensive. Scuzzys comb/Ramtors spellbook are another step up.
Also, if you have main attackers that do in the neighborhood of 8-10 icons, an Illusens Earth Potion as a bomb is no good. That bomb only does 6.33-9 icons, so you'd be better off using your main attackers. If you can't afford a honey potion, use one-use bombs like the cheap sticky snowball, tortured snowball, snow mudball, fire muffin, etc. And for the healer, I'd suggest a greater healing scroll, as it's very cheap and will be good from the time you're low-level until you have 100 or even 150 HP. I agree with poohroony's suggestions of scarab ring, leaf shield and snowglobe staff.