@ rofish
Don't find your questions dump at all , this is , what such forum sites are made for

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Indeed those lures are tricky to make , at least when you start out from almost zero as I did many years ago .
In theory it is true , that the fatter , more buoyant tail end of a "Banana"-lure should let the narrow lip portion hang head-down in the water , but on most of the lures , that I made , it did not significantly

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Surely the harware on the rear portion plays its part in this matter , don't underestimate the leverage of the tail hook at the very end of lure , it also has to do with the size of the lure and its buoancy in general .
But I guess , that I can't give you a very good and logical explanation about it , maybe it also has to do with the different shapes of both ends of such lures

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I haven't tried splitting the weight fore and aft , why should I do that ?
Any weight in the rear would be counterproductive , I believe .
Most of the crankbaits I made , have their balance weights somewhere between belly hook and lip(or just close behind belly hook) , this most likely enhances a stable running and increases diving performance , whereas a rear weight slows both of these features down , only probably provides better casting performance , but why should I cast a lure far out , that doesn't run well ?
Only found very few exceptions to that rule so far .
To put leadweights into the narrow lip of these lures is also not that easy , there is not much room for it , due to the groove of the toweye wire form(though I did it before left/right of that groove) , that's why I most likely put the weights in front of the belly eye .
The weights required on a 3" to 4" bait are not that heavy at all , f. e. the models mentioned below do already have a considerable action unweighted , but just that one leadshot renders it more stable in wobbling performance .
To get more information about how to rig the toweye , please check my uploads here in the gallery , there are three pics there called "line tie construction" , these should answer your questions

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Finally I'd like to mention , that "Banana's" around 3" to 4" are the easiest ones to get to run properly , smaller and larger are more tricky .
The model shown in my previous post(three in water , one laying on a sketch drawing , one causing wake) , in above mentioned sizes shouldn't cause too much problems .
I make these of abachewood , light , but yet strong enough for screweyes .
Greetz , Dieter