Experience Penalties
Remember that EXP. penalties multiply, not add, so an iksar shadow knight requires 68% more experience than baseline, not 60 (1.4 [SK penalty] x 1.2 [iksar penalty] = 1.68 or 168%). It also works the other way, like for Ogre Warriors, who require 3.5% more experience than baseline ( 0.9 [warrior bonus] x 1.15 [ogre penalty] = 1.035 or 103.5%).
As far as penalties, soloing, and whatever else goes...play what you want to play. This is a classic server with normal experience rates, so you are going to be looking at whatever character you pick for a long time. Don't pick it because its the best at end-game, it'll be a while before you get there. Pick the race, class, diety, and bonus stats that you want for the journey, because the journey -is- the destination.