Directly from the notes on page ONE. "IF the 510 does not fit flush, buy "510 Varitube v2" connectors for the RX200s and DNA200s that you plan on working on, AND extra 510 connectors in case any of them breaks, so that you can fix them." I bought an assortment of parts for several of my mods because YOU need to be able to fix everything that breaks from here out. Look at what is on the RX200 and buy accordingly. The documents below will also tell you what to buy!
Here is an ECF document on fixing the RX200 model 510 pin:
Replacing the 510 in an RX200
Here are the two videos you need to watch on repairing the 510 connection for the RX200 models. The second video is in French, but the video is really well made and makes it easy to follow.
RX200 510 PIN REPLACEMENT TUTORIAL | MODDING MODS EPISODE #4| DAVE GEE
Tuto connecteur Fat Daddy sur Reuleaux RX200 (IN FRENCH)
A new video on the RX200 2/3 by DJLsb wherein he also replaces the 510 pin with a Varitube model:
The Undesirable Review of the Reuleaux RX2/3 + 510 Connection Replacement