Basic Answer:
You’re best bet is to make neutral spawn points with team-owned Spawn Zones.
Spawn Zones:
Spawn Zones are best thought about when you assign them a numerical value. That’s right, math. Yay. Anyways, let’s say that a normal, or “Strong” Respawn Zone has a value of +500. A Weak Spawn Zone has a value of +100 and an Anti Spawn Zone has a value of -100. All respawn points have a starting value of null (0). Also, Initial Spawns are not affected by any Respawn Zones. So, if your map is only supposed to have spawn points at bases, then you can just use Respawn Zones owned by the team that the base belongs to. However, if your map has bases and then many “Side” spawn points (spawn points that are not supposed to be for a specific team) or if the map has no bases, then it’s a bit more complicated. In this case, it is usually best to cover your entire map with a Neutral Respawn Zone, as that will allow for all respawn points to be used. It is important to note that two of the same type of Zone do not add anything. For example, if I place a Weak Spawn Zone on another Weak Spawn Zone, that area still has a weight of +100, not a weight of +200. The only time zones add together is in the case of Strong Zones. If you place a Strong and a Weak Zone overlapping, then the overlapped area now has a weight of +600.
Strong + Strong = +500
Strong + Weak = +600
Strong + Weak + Weak = +700
Strong + Anti = +400
Strong + Anti + Anti = +300
Weak + Weak = +100
Anti + Anti = -100
Weak + Anti = 0
Weak + Anti + Weak = 0
If you don’t get it, then just take a screenshot of your map and I can give you some advice on that.
Spawn Point Advice:
The basic rule for placing Spawn points is that you should place them everywhere on your map that can hold them. However, when a player spawns from a point, they should be able to walk forward for 3 seconds without hitting anything.
Getting Maps Noticed:
This is the hard part. What you’re going to want to do is play the map and advertise it. Go to all kinds of sites, such as Reaching Perfection, ForgeHub, ForgeWorld, Forge Cafe, XForgers, any site you can, and make a thread for it. Once that is done, find custom game nights to play your map in. If people like it, they will show friends, who will show friends, etc until it reaches a Community Cartographer. CC’s are Bungie’s people that watch for community maps that are worth at least looking at. Your biggest goal is to impress them. However, I do not know if 343 is using their own CCs or using Bungie’s CCs.
Hope this was helpful, let me know how it works.