The difference between tritium and deuterium production is rather heavily weighted in favor of Deuterium by a factor of roughly 10:1, more if you count day/night cycle. This bottleneck is primarily in the fact that Solar Neutron Activators are extremely slow. This leaves a reactor build requiring a ridiculous number of SNAs in order to match production between the two gasses.

Since SNAs are not particularly difficult to build, and since there is an existing bottleneck in brine -> lithium production, further bottlenecking the process with slow SNAs really just pads out the build needlessly, especially since they're sunlight dependent, which doubles the number you need to around 20 per deuterium chain.

Further, needing 20 SNAs per deuterium production chain will potentially be a lag contributor. Considering that running a reactor full-bore will require around 5 individual deuterium chains, that's 100 SNAs on top of the brine production towers and condensitrators you would need to build to keep lithium production up high enough to deal with night, weather, and non-ideal biomes. With each SNA having associated conduit as well as their own tick load, if more than one or two people on a server try to build a fully-active reactor, it's going to add an not-insignificant amount of load on a server. And, regardless of apparent lack of practicality of doing all that, people will still build it all.

It seems more reasonable and server friendly to boost the SNA production and leave the bottleneck as the one that exists at the lithium production level, requiring at most 1 or 2 SNA per lithium producing Solar Evaporation Tower pair.

Scaled up by a factor of 4.