Why don't "Koranists" just become Hanafi's?
However, it seems that it would make more sense to follow Imam Abu Hanifa's school of thought, at least in this way you are more in-line with the orthodox opinion, and following one of the 4 established schools.
The reason I say this is because:
Imam Abu Hanifa [rahimahullah] felt it was more correct to use qiyas and derive a Qu'ranic principal [which could apply to other than what was directly being referenced in the ayat] to make a ruling, than to use an ahad hadith.
He would only use an ahad hadith if 1) it didn't contradict Qu'ranic principals, or 2) it was well known by the Tabi'in.
This seems to be a more reasonable opinion to me, than rejecting every single ahad hadith in all cases and using your own judgement, when there is an authenticated statement of the Prophet [s] available, even if it only is "ahad."
[BTW, ahad hadith can come through several chains, not just one, as some people falsely assume].
So, why not just become Hanafi's? Makes much more sense, and in such a case you would be following a student of the Sahabah, and still keeping a majority of your "Koranist" views [though not all of them].