I'm probably not the best qualified person to talk about Nerve tuning - I'm happy to get the thing working and call it good!
However, I'm sure that you'll agree that getting the marker running at full velocity is as good a start as any - fine tuning and experimenting with different combinations of settings can come afterwards.
With that in mind, the one thing that you haven't actually mentioned above is the LPR pressure, so I am not sure how you have it adjusted, but there is a fair chance that if your dwell and HPR pressure are set sensibly, your LPR pressure may be too low.
Unlike with some marker designs, were the basis of LPR tuning is just to get the bolt to cycle reliably at the lowest pressure, with rammer and poppet markers such as the Nerve (or hammer and poppet for that matter) , you need more than the bare minimum cycling pressure. The LPR pressure has to propel the rammer up to a velocity where it has enough impact energy to open the valve enough to achieve good air flow. Doesn't matter how long your dwell is, if the valve only barely opens, you'll not have good air flow, acceleration of the ball will be very gradual, and your velocity will be low despite sensible HPR pressures and long dwell times. Irrespective of your other settings, your LPR pressure has to be high enough to knock the valve open.
So, a good initial approach to setting up your marker would be to set the dwell correctly for whichever solenoid you have (on average, a Humphrey solenoid requires longer dwell times than a Parker), set the HPR pressure within the recommended range (Smart Parts state 200-280psi, with 230psi being considered the average, but many people set their Nerves lower than this), and then adjust the LPR pressure until you have full velocity. That way you know that the LPR pressure is in the right ball park. From there you can fine tune your settings 'til you have them just how you want them.