I'm currently playing a level 54 LF Javazon. The problem is, I can never use more than about 8 LFs before my mana bulb runs dry. I have 10 ML, twice what the guides reccommend and I still never have enough mana to throw more.
I've asked people if AR matters and they've all told me no.
Insight on your merc. . .hmm. . .Would it help- yes- as long as he stays alive.
You effectively change your merc from a helpful killing tool (one that can provide you with WAY more valuable auras) into a Mana generator. When he dies. . .like he so often does when holding an Insight stick. . .you're dead in the water.
The solution to your problem is rather simple actually, and you don't need any fancy runewords on your merc, and you don't need to upgrade your Titans (although both solutions would help).
1. You need items that give you + mana for each kill. You might not think that this would help too much, but it does- significantly. Especially with the killing power of LF. Even at +5 mana per kill. . .If you throw ONE Jav and Kill 4 things (not uncommon at all) you will get 20 Mana back. There are many common items that give +mana after each kill, so no super duped runes are needed, and you don't have to trade the farm for some exotic Elite/Exceptional Unique piece of equipment that you would have to pump Str or Dex through the roof to equip. Simply have a ring or maybe an ammulet that has maybe +5 or so each and that should help alot. There is also the Tir Rune -very common and provides +2 mana after each kill. Won't cure you, but it will help.
2. You need Items that increase your mana bulb. A bigger mana pool to draw from has benefits other than # of consecutive times you can cast your spells. Try to get items that increase your Mana. Again- this won't cure you, but it will help alot.
3. Mana regeneration rate- You can't have enough of this. There are many items that increase it. Try to find some.
4. Leech. The last piece of the puzzle is leech. I say last because in my mind it is much easier to come by, and I believe there is more to be gained by using the other methods. Leeching only happens off of the physical portion of your attack. Much of the damage from LF happens from the Lightning and therefore is not used in the leech calculations. Shoot for 20% and see if your bulb stays a little more full.
assuming this zon is not for pvp, then get some sojs if you can afford.
Making a good javazon is not cheap, if you can't afford good equip, I wouldn't make one.
not too expensive
weapon - titans
helm - valk wing the 2-4+ mana per kill, skills, frw, socket it with a tir if u want
shield - spirit ~100 in to mana 2 skills and resists, o and 55fhr
Armor - vipermagi/skulders/que heagans plenty of options for resis/mf/mana
belt - tgods/razortail/glooms trap
gloves - 2/20 rares 3/20 magical gloves arnt too hard to come by
boots - silkweaves for mana
rare rings and cats eye ammy