I'll just leave this here.
Suffice to say, it's possible to get up to 160% (or 140% depending on interpretation) effectiveness.
There are better uses for the feats though. Also, regarding the Solar wish engine:
"A controlled creature can be commanded to perform a service for you. Such services fall into two categories: immediate tasks and contractual service. Fighting for you in a single battle or taking any other actions that can be accomplished within 1 round per caster level counts as an immediate task; you need not make any agreement or pay any reward for the creature’s help. The creature departs at the end of the spell.
If you choose to exact a longer or more involved form of service from a called creature, you must offer some fair trade in return for that service. The service exacted must be reasonable with respect to the promised favor or reward; see the lesser planar ally spell for appropriate rewards. (Some creatures may want their payment in “livestock” rather than in coin, which could involve complications.) Immediately upon completion of the service, the being is transported to your vicinity, and you must then and there turn over the promised reward. After this is done, the creature is instantly freed to return to its own plane."
It is far easier to accomplish the same thing using Efreetis instead of Solars though, and that leads nowhere good: that is the shortest route to creating Pun Pun if you use Candles of Invocation and exploit Pazuzu. In that case, you create a genuine infinite wish engine, rather than simply bypassing the 5,000 EXP cost.
Edit: how did the conversation shift to Solars in the first place?