i want to make the system mine, not any system
That probably depends on just how specific your requirements are.
- decent number of bodies, maybe some planetary rings: there are thousands of these scattered about the existing edges, you might not get your first choice but you'll get something, especially as existing claims continue to be completed and expand the collective radius further
- has specific personal value to you but nothing quantitatively unusual: chances of anyone else happening to rush for this is tiny
- ELW: there's probably only a few tens of these available at any time and they're really obvious targets, so no matter what the rules are you're probably not going to get one at this stage.
- in a nebula: chaining out to any non-Pleiades nebula is a major project with multiple tens of steps needed; you can probably assume if you're trying to do it solo that some organised group will overtake you anyway because they're really obvious targets; organised groups would generally be inconvenienced by "snipe protection" because they want to be able to spread out the architect roles anyway. But nebula are big enough that if you're sniped to one system you can get another one that's also got a good view of it
- a specific system in a distant nebula: there is no level of snipe protection possible that would prevent one organised group chaining out thousands of LY, and a second organised group just racing them to the finish line from a few systems back.
Isn't that going to be around 2500 ly out the bubble?
At the end of last year I found some previously undiscovered systems - including an ELW in one of them! - slightly under 1000 LY from Sol (though far enough below the galactic plane that it was almost certainly unchainable in that case). But the 15 LY range limit means you have to stick fairly close to the galactic plane, so 2500 might be a reasonable guess in those directions (unless you're into brown dwarf systems, but you probably don't need to reserve those)
I believe this is fair because if they are the ones who did the legwork to work out to a system them imo they at least deserved a shout at calling dibbs
The Architect doesn't have to be the same person as the majority contributor to the hauling, though.
(Indeed, the Architect doesn't have to haul a single tonne themselves, in theory)
A rule where the largest individual
hauler to the system got first refusal on onward colonisation for a short period of time might be justifiable on the "legwork" basis, but the consequences of doing so are obvious.