I did Ceos/Sothis in a Python, an Asp and an Anaconda. My thoughts:
The Anaconda is the best ship for the long-haul cargo delivery missions to the bubble out of Ceos/Sothis and here's why:
The Python is a great ship, pretty & nasty, I love flying it but while the cargo cap seems huge compared for instance, to a Cobra III you quickly realize the Anaconda can earn triple as much credit per lap (back & forth to the bubble) as a Python while making about a third fewer jumps due to its much longer jump range compared to the Python, especially modified. The Python, while OK for hauling medium cargoes medium distances just doesn't have the greatest jump range or cargo capacity. It can be done though:
39 jumps to the bubble!
My easy, second choice is the
Asp-X. If you already have one or can afford one, consider an Asp-X for Ceos/Sothis since early on you will not necessarily be trying to fill your hold with long-range delivery missions. Depending on your level of local REP & INF you may need to run a bunch of data delivery missions between New Dawn Station in Ceos system and both of the stations (New Dawn & Sothis Mining) in Sothis system to increase your local REP & INF and become ALLIED so the more lucrative smuggling and cargo delivery missions begin to be offered. The Asp-X offers the flexibility to carry more of those missions due to its ability to land at Sothis Mining. It also carries
enough cargo that you can easily earn 15 million per lap back to the bubble on those long-range cargo hauling missions.
After a few of those you really start paying attention to the increased cargo cap and earning potential of the Anaconda. Though over your 100 million budget (more like 500 million if A-rated) you can basically buy another new Python after each Ceos/Sothis/Bubble run made with an Anaconda. It has good cargo capacity, good legs (better with engineer FSD mods), good guns and a good earner. But it is expensive and has a couple of limitations:
The Anaconda cannot land at Sothis Mining, the "other" Sothis station (there's no large landing pad) so the Anaconda is limited to using Newholm Station while an Asp or Python can also land at Sothis Mining. Not major but some might find it limiting. Also, in its "stock" form, flying an Anaconda is like dancing with a fat lady. The Asp-X and Python are both more maneuverable and flexible and the Asp has longer legs, the major (to me) trade-off being their much lower cargo cap. I find the Asp (and Python) to be much easier to fly and dock than the Annie. The Asp has much better visibility as well. I still trade off between using my Anaconda and my Asp-X for running Ceos/Sothis.