High Boost Engine Timing and E85 Limits

Just have a question on what engine timing on a drag engine would look like on 70-80PSI. Does the engine timing reduction per pound of boost plateau after a certain boost figure for that engine/fuel combo? Just seems like timing would start to go towards ATDC.

Also how would you know the limits of a known fuel such as e85 on very high boost engines without grenading he engine. From my understanding, any knock on High boost figures could prove disastrous. Thanks in advance

So why would you run E85 and not a full race fuel?

Just asking. Not real world. Ive seen some guys running ignite e90 and just wondering where the limit for this fuel would be hit and when other fuels would be beneficial such as Methanol.

David Ferguson, E85 produces better results than the common race fuels (C16/Q16) in most cases.