If it’s just one particular species, perhaps pile in all your pictures with text. Add the Species ID and then a further ID of Tarax. Or just Tarax, with an explanation and then, when ready, add the Species
Yes, agreements will come and may even overload but the Species ID will remain for Agreements as you refine the Text/Photos.
It is no bad thing to see our posts at higher taxa than we would prefer IF there are good notes and a comment trail.
We see, from a quick browse, that species, rarely get agreements (just one would be nice!).
My feeling is that it is best to show what you have, demonstrate how meticulous you will be and what you have in mind and to hand. To those who are really interested in the process of IDing it will be very nice to watch - a few people will Favourite it, no bad thing.
You are allowed 15 pictures in an Observation, though don’t put in the 15th until the final edit. They can be reordered, removed, replaced.
I might be tempted to make a project, It does NOT have to collect Other Observations, though you could make it specifically collect the one you have IDd (there won’t be many). But it can hold all the text and references you need and 10 pictures. It does not need a complex map.
Subsequently a few things might happen
You may conclude it is not that species after all - that will not matter, as an added ID will supercede the first but not override the Tarax. (if there are agreements) we could be asked to co-operate.
You will almost certainly generate a Comment Trail that could be very valuable to the final outcome.
You can modify text, add and remove pictures, delete the whole thing and begin again. You can retain (copy) valuable input and add it as a first comment in any new post.