Hey Nowhereman.
I'm having the same problem.
I have considered using a combination of both oral ingestion and intranasal ingestion. Some of what you snort will end up in the stomach either way. Maybe it's even worth doing some sublingually (under the tongue) as well. It sounds like you, like me, are not willing to get involved with needles and all that. But, as you probably know, IV is the fastest and most efficient ROA, as well as negating any possibility of the substances being expelled by the body.
I plan to use antiemetics, probably a regiment instead of just a stat dose (although that does mean having a long time to get nervous and potentially have second thoughts).
In terms of protocol, it might be a good idea to follow Stan's Guide to SN as a reference guide. For example, for the antiemetic regiment, and he also suggests things like using as little water as possible to reduce/prevent vomiting etc. Some of it will apply, some of it will not.
Also, Fentanyl alone could easily fail. I plan to use Valium and either Amitriptyline or Propranolol. I will probably also potentiate with a small amount of alcohol (spirit), as suggested in PPH.
Cheers,
Microwave