A theologian may be able to provide a valiant attempt to marry empiricism with religion
Most theologians don't care to consistently make claims based on evidence and other verifiable sources. Its a hodgepodge of evidence, philosophy, speculation, and fervent belief.
but the observable reality that the senses provide run contrary to systematized religious belief
The religious would disagree. They develop complex explanations based on unverifiable claims and assertions (speculation). For example, lets say you are debating a pixy-believer. They might assert that gravitation exists, causes objects to fall at 9.8m/s/s, etc... and we would all agree. But they would also claim that its caused by undetectable pixies holding everything down. Such a claim is unfalsifiable and thus useless because there are a limitless number of unfalsifiable claims that can be made.
Many religious think that presenting unfalsifiable claims is a sign of the strength of their argument when it is actually a telltale sign of weakness. This is why you often hear the statement "you can't prove god doesn't exist". Rather, the religious should be saying "this is why you should believe god exists" and pointing us to objective reason and evidence why. For example, who finds this argument valid "you can;t prove pixies don't exist".
And then there are the fideists. Those who think that "faith" in their beliefs is justification. But that is a whole other can of worms. Great thinkers from long ago (both religious and non) have destroyed the basis for fideism. Suffice it to say, fideists claims have indistinguishable truth value from ANY other faith-based claim.
To sum it all up: The difference between science and religion is that science finds answers and religion asserts them.
should aforementioned religious belief be based on something other than grounded fact.
Well there are lots of things that aren't (directly) based on grounded fact. Like which flavor of ice cream you prefer or the meaning you find in particular books.
Once the theologian must resort to speculation to reconcile inconsistencies and grey area, then he/she ceases being scientific.
The religious would retort by saying they have no intention of being "scientific". That religion and science are two separate issues. The religious would be correct. Their beliefs are not scientific, but they
1) fail to support their position with something else that would justify their claims.
or
2) fail to acknowledge the limitations of philosophy and speculation.
This is where they fail.
The only way to marry this rationalism and the empirical world is for both to "give" when necessary, and the dogmatic aspect of the major world religions would never allow that.
Rationalism and the way we think stems from our interaction and experience with the physical world. But the religious cannot support their extraordinary claims by the physical world alone. To bypass this seemingly insurmountable problem, the religious often speculate about alternate realities or "true reality" (E.G., heaven, hell, timeless gods, souls, spirits, demons, transubstantiation, resurrection, etc). They build fantastical castles in the clouds and expect you to ignore the absence of testable, observable support.