Nicely done, Steve.
Did you fit Mercury or Meteor 'O' rings? If the former, make sure you keep a watchful eye on the power potentially creeping up.
My .22 Supersport makes a lot more power with Hobby vs Superdome. If you have any to hand, it's a good idea to power check with the Hobby. I haven't power checked my Mercury S with anything other than Superdome as yet; but as it's safely under, all should be safe.
Also worth treating yourself to some H&N Excite Hammer from our good sponsor. Cheap as chips and excellent quality. Both my .22 BSAs love them.
Lightning- there have been a few threads and also, I think, an "Idiot's Guide" over in Collectables. You may have to "drop" the front sear to allow piston removal and I think it'll have the Maxigrip? You'll also need to obtain / make a dowel to clear the spring and exert pressure on the spring guide to facilitate spring removal and refitting. But not too hard at all.
But, yes, I saw it written many times years ago, but it does seem that the higher quality rifles, like Weihrauch and Air Arms, are easier to work on. And I'd generally agree with that. Fit and finish are better, too, and they're just so much better engineered and made. But, then, working on some of those lovely match rifles of yesteryear won't be so easy (especially the Giss Dianas), so I guess that dispels that!
Have fun and be sure to shout up if you need any help.