Cyclopse,
It sounds like you covered all of the basics--I would look primarily at loading and VTA when there is an issue of tonal balance. Perhaps you could try loading down the cartridge a little more (lower number, like 125 ohms or even lower number). That tends to increase the bass response, though at a loss of some top end extension and "air."
After about 50-60 hours of use, the cartridge should be substantially broken in. That is the point to again try experimenting with both loading and VTA. In some respects the two parameters are interactive in what they do to tonal balance so you have to try different mixes of the two (assuming you don't deviate too much from the top of the cartridge being parallel to the record surface).
When you say bass is light, are you talking about truly deep bass or a kind of lack of warmth associated with midbass/lower midrange (say 60-200 hz)? Most Lyra cartridges are NOT warm. Also, what are you comparing to the Delos (your prior cartridge)? If it is something like a Koetsu or a Grado, it will NEVER have the same kind of midbass weight and warmth.
Good luck.
