I have some quibbles about the research priority.
I would get more engine boost technology before I would research small fuel tanks, just as an example. But I really appreciate you post the techs you have with the ship, that helps the discussion a lot.
I REALLY like small scouts. Playing around with parasite scouts has made me leery of sci-fi settings where they DON'T have expendable drone scouts or scout craft in general. Any space battle, one of the huge conflicts is going to be around scouting and detection.
My love of small scouts started in a game where I decided that I wanted to build fighter factories early, instead of just ramping up once I got some 'killer' tech that made fighters viable. I figured it would be more organic if I was already using fighters for something, and there would therefore be more interest in developing technologies that could be applied to an existing industry rather than developing the tech and the industry at the same time.
My first scouts were jump-scout pinnaces. I built them with the bare minimum jump technology. 200 ton ships with 1 HS for fuel efficient engine, 1 HS for jump engine, a 1/2 sized engineering system, some fuel and crew quarters. I figured about 3 year endurance was good for scouting out new systems. They were slow, but they allowed me to scout systems for aliens without exposing more expensive ships. And because they were so small, I didn't have to worry about them revealing the jump point to aliens. I had one scare where the aliens followed me into the system I scouted from, a system that happened to be adjacent to my home system. Fortunately there was a loop, so I could have my scouts disengage the OTHER direction, and jump out once I was utterly convinced the enemy wasn't in range. 7 freaking Swarm Motherships.
I research efficiency 5 jump tech pretty quickly, and that becomes the basis for my jump tenders. My second generation jump-scouts include both 250 ton and 500 ton ones. The 250 ton ones have 2 HS for engine, a .1 HS active sensor, and the 500 ton ones have 3 HS for engine, and a 2 HS sensor, usually an EM sensor. EM is the most reliable way of detecting an enemy without them detecting you. If they have a big noisy anti-ship sensor, my EM scout can detect and maneuver around them.
Once I have a lot of survey support carriers and jump tenders, I start using a couple of new classes of fighter scouts. Instead of just face-checking rocks, which requires 60 billion km range or so to do efficiently, I have forward observers. These are fighters designed to maintain an active lock on an enemy while staying out of range. They have much lower crew endurance, and much more boosted engines.
My 3rd gen system scouts are bare bones, 1 HS of boosted engine, .4 HS of fuel, .1 HS of active sensor, for maybe 80 tons. They are cheap as heck, fast, and have decent range. The cheap part means I can afford to have them everywhere. My colonies have a carrier PDC that bases a few scouts and a fast beam fighter for killing enemy survey craft. Because the 3rd gen scouts don't have mass for maintenance, endurance or jump engines, they are far more efficient, but they depend on the infrastructure of the survey support carrier and tender.
My forward observer designs currently are 3 HS for engine, 1 HS for fuel, 1 HS for sensors, for about 300 tons. Unfortunately just above that of a boat bay. I really want a 50% of HS in engine speed for my fast scouts, but I suppose 40% might be acceptable. I really like having the speed cushion. I would prefer a 500 ton hangar design, so that your patrol cruisers can also host up-to-date war fighters as well as scouts.
I also have 15 ton Long Watch 'fighters' that are nothing but 60 year of crew endurance to simulate an automated sensor outpost. I name their task group after the jump point they are stationed at. It has a downside in that I have a lot of MN (monitor) task groups to scroll past, but I have a quick way of checking if I have a sensor outpost at a particular jump point.
As my economy improves, the plan is to put more capable sensor platforms up. Platforms that have a 1 HS res-1 active sensor, a full sized engineering system, designed as a commercial (no maintenance, no crew morale issues) early warning system. For around 40 BP. The cost isn't just the platforms, but the micro involved in placing them.
The beauty of fighters for scouts is that you can have as many different types as you want without retooling. A downside is that you have a huge variety of craft to manage.
Scout effectiveness is all about size. The size of your sensor relative to your cross-section. So small scouts with high ratio for a single sensor are highly effective. I distinguish scouts from forward observer roles in my tactics and scout design. A forward observer has to maintain an active lock on an enemy, so it needs speed. But since it is part of an assault force, it generally doesn't need endurance. Scouts have to have multi-year endurance so they can spend as much of their life on scouting and not on travelling to and from the frontier and resetting maintenance clocks in a hangar.
It takes a bit of experimenting to figure the right ratio of scouts to survey ships to always have scouts available to scout newly discovered jump points. Obsolete jump scouts are still useful for a long time. They may be slow, but they can be immediately available.
