Hi btw, I'm new
From my understanding the shaft is best used without a crosshair in that way you aim the shaft not the crosshair which negates the lag. I have an eractic ping at the best of times (my isp or my network whatever I haven't solved the prob) but even so I'd still use cl_truelightning 0, I'd rather know where the shaft actually is.
My advice switch off your crosshair, add it to your shaft bind, and head to pov.
IMHO cl_truelightning is irrelevant, probably does more harm than good but if it works for you then use it, lift the ban.
No, absolutely not. The lg is like "machine gun", it hits the place you aiming at 100ms intervals. The lagged graphic presentation does not do damage after the initial hitpoint has been determined. This is why you should aim directly to the enemy when using lpb pings like 12ms or 25ms or even 38ms. Anything above that requires some "prediction".
Also about the truelightning, it does help the people who get confused with the graphic presentation of the lg. You can pretty much negate this effect using larger crosshair that doesn't get lost in the action. This is also the reason why hpbs think it will help their lg-aim, they just don't do wrong aiming corrections since the lg doesn't confuse the player and they aim more with the real hitscan spot (that is crosshair).
Should the truelightning be banned, I don't know. I've used it myself in the past for a long time, but I don't use it anymore. My lg wasn't any better with truelg 1 or 0.5 or any other value than it is with 0 but I've played so many years with ping 25 (or lately 13ms) that it explains the thing somewhat.
I know some people that have tried using truelg, some of the said it is really horrible and makes their aim worse, others said just the opposite. Perhaps it helps some players but I doubt that, probably depends on the player pretty much.
If you want to improve your lg, just practise it on something else than povdmm4. You can always use bigger crosshair that might help a bit. Also you can change the lg-texture and you can use gl_shaftlight command to dim it if it's "too visible".