Why not start us off with your pace difference?! Is there any reason to assume that your difference in pace wouldn't be normal?

I don't know how much difference it makes to me exactly, I would guess about 3 seconds per 100m.

I wasn't watching the clock for most of it, but the one I did notice was 400 in about 6.10 instead of (I guess) 5.55.
This was a bit more than I expected, but I was also feeling a bit tired.

I never trust how I feel in the pool though as the clock frequently tells me otherwise (both ways :-) )

50m are rare in the UK so we don't switch back and forth as much as people in the US seem to do.

About converting the paces, I can't answer that but my experience is that there is very little difference for myself as a "slower" swimmer. I regularly bounce between 25 and 50 meter pools and swim pretty structured sessions with a fair amount of work with a tempo trainer "beeper". I find the biggest difference is psychological and it doesn't seem to be much. I am no means an expert in this area but I believe the biggest gains in changing direction are related to the streamlining and dolphin kicking underwater. So if you don't do this well or at all then the gains off the wall would be smallish. And I can't dolphin and usually do open turns so that fits me to a tee.

In this manner of thought, I was in a 25m pool a few weeks back doing some work at around 1:40 per hundred which for me is threshold. A young guy in his 20's who looked to be in pretty good shape showed up with his girlfriend (it was a beach resort type of place). He didn't appear to be in for a serious training session. After he warmed up a bit he was able to dolphin underwater the entire length of the pool AND he was doing it much faster than my 1:40 per hundred pace... he would literally just blow right by me like I was standing still. Pretty impressive.

I am certain Dev and others can give you something also...

I swim 3x per week, pretty evenly mixed between scm and lcm.
I am very consistently 3sec/100m slower LCM in training
It's closer to 2s/100m in a masters meet

Thank you.

If I am doing a set of 100s I am about the same. A set of 200 or more it can grow to closer to 4 seconds per 100.

I think It is not just the push off that matters. Even over just 50m stroke rate slows down quite a bit without the 5 second break every 15 seconds.