The first shot out of a clean barrel may be right on or it may be off a bit.The only way to know for sure is to try it with your gun.My own hunting rifles will shoot 1/2" groups with the first three shots out of a clean barrel so it is not an issue for me.

My POI doesn' t not shift after cleaning my rifles or MLer, thus i do not hesitate to hunt with a clean bore. Are you guys leaving oil in your bore? If so this will increase the pressure and can cause POI shifts, I always a dry patches through before shooting my rifles to remove excess oil. The oil not only can shift your POI but be both harmful and dangerous. Now i will admit some guns do require fouling but not all guns, it is best to find this out through T&E and adopt the correct formula for cleaning/hunting with regards to your gun.

Go to the kitchen an get some vegtable oil. No petrol smell

I wouldn' t worry about that little bit of smell, also you have almost 2 weeks for the smell to die down. If you do clean it, make sure you shoot 1 or 2 fouling shots. Some guns may not need to be shot after cleaning but I know my rifle does need at least one fouling shot. Good luck.