Yes BP ETA case. You won't ever fit these Raffles ETA dials in s BP 3135 case.
I used the 28.5mm one. I knew it was getting shaved and figured it would be an easier fit. The 29mm dial is a SWISS - T < 25 dial
I don't think the markers are too big. remember it's a bigger dial. But yeah a marker swap is possible.
Yes you can *usually* remove a cyclops though I've had a couple that just wouldn't cooperate and either cracked or left chipped cyclops remnants.
The BP inserts are ~37.4 OD (gen 16610 is ~37.65) so that works well for a 14060 which has a smaller insert than the 16610