I thought I might have to design in some leeway at the butting ends, but didn't bother and it wasn't necessary, the parts clicked together fine, tight enough. If the overall diameter has increased a little, it is within tolerance.
I have not been bothering with brims or rafts since I started with the 2S (heated bed, textured build plate), but I could not get a sample print without it warping and I couldn't get a good first layer with just a brim, so I returned to using a raft (which I find pretty much essential on the Tina2), and it worked like a charm.
I'm using Elegoo PLA+ at 210ºC, first layer 215ºC and slow, 60ºC bed. I keep my filament in a dry box, which seems to help too (but that's unproven).
I hear a lot of chatter (social media) about warping starting at corners and if you pin corners down with mouse ears or a brim you lessen the risk. Well, for one thing, if your print occupies the majority of the print bed there is no opportunity to add mouse ears, and for another – I've printed circular things (no corners) and they've warped! And you can only combat warping on the print bed, not for overhangs higher up.
