Well - I don't think you need any tech, you should be able to strip the non- Construction modules out and drop in a second construction module.
That will put you at 99 of 108. Though to get any more you need more "Capactiy" whcih the first is "Storage Maximization" 2 techs in under Engineeering. Then you have "High Capactiy Hulls", again 2 techs deeper (Under Zero gravity Construction - medium ships).
When I have a choice I always go for +Capacity, then trade for the other techs.
Note: once you have a base already positioned, you don't need scanners or life support on a constructor to move it from Shipyard to base, so I recommend stripping them off, and adding either engines to get it there quicker, or more construction modules. Note: you often do want the above when sending out a new constructor to create a new base.