For generalities and an overview of B&W reversal I usually refer people to this
Analog Resurgence video. It covers one approach to process and shows examples with several films.
I've not tried UN54, but if it's anything like Kentmere 100, it is an ideal candidate for reversal. I get full speed out of Kentmere 100 and 400 (with a slight increase in the 1st development time) using stock Kodak D-19 as 1st and 2nd developer. If the finished slides are too dense you can increase first development time, rate the film slower, or do a 'reverse chemical pre-flash' with a dip into a weak ferricyanide solution and a re-fix. I prefer those techniques over adding thiosulfate or thiocyanate to the first developer to control density.
Fomapan stocks are a great place to start practicing with reversal because you can use stock dilutions of common B&W developers as a first developer and get good results.
Can confirm: it is easier to block your highlights with XX. Rate at 320 and develop for 200, especially when using it in high contrast daylight. I haven't noticed much in the way of halation, but I'm more used to effects you see in x-ray film so I may be overlooking it.