I understand what you mean about killing reactor first, but for this you will really need teamwork and a second experienced builder, (how often does that happen? ussually its better off when the experienced players are covering the builder instead of leaving newbies to cover you) also as I said, it depends on the distance you have to travel with your team, sometimes its just better off to killing reactor as soon as you spawn and putting it up as soon as you get there, talking in teamchat, and waiting for a teammate to kill it is also giving time for the enemy to attack you. Of course, if you have another experienced builder, telling him to kill reactor works, and he can aid in building the new base, relocations with 2 builders or more go quite fast.
I've seen quite a few times people that just wander off with their ckits to the new location by themselves and then ask for reactor to be taken down, 90% of the time, this ends with a lonely reactor on the other side of the map, and a bunch of dead humans. Having people to follow AND cover you (which can be quite frustating sometimes) is the key to successfull relocations. Maybe coordinating with the whole team isn't needed, just know who your 3-4 best players are then get them to pay attention.
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I guess you could do a server with ~16 public slots and ~10 private ones or something like that.