As someone that flies DDD a lot extra links to help I notice a difference up to 6 links, the types of links also matter personally I go for 1 opti, 3 tracking if I can get it. If I am able to get 6 links the last two are another opti and tracking.
DDD's mostly have heavy waves 2nd spawn NRF, 2nd wave TPPH and good DDD's with links have no issues in TCRC's. The only other wave that's a little bit of a pain is 1st room TPPH if the links are late.