No mate, I love talking about f3b and models and stuff.
I have mks 6125s on the flaps, with 6125minis on the ailerons. 6125es in the fuselage (this setup eat battery quite fast - beware!). The wing servos use fu bearings on standard linkages (not rds obviously). There is nothing particularly note worth to say about installing the wing servos. It just the same as a normal model.
one thing to check is the the tail ball links. on mine they were very tight and I had to ream out some of the plastic connector to get a more satisfactory movement. It works anyway, you can tell the difference with 2 clicks of trim easily (i.e in distance). I wasn't really in love with the supplied connectors for the fuse servos either. I would prefer to have used a bearinged metal ball link or something but the centring seems good, per my comment above.
The ballast is fairly user friendly. I would however say it is a bit of a weak point compared to other models around. It works fine, but having to cast lead strips which tend to rattle around a bit inside the joiner isn't that brilliant compared to most models now which use brass (non toxic) ballast that slots in nicely.
If I want to use full ballast I have to remove a nose weight. Up to 3/4s it balances the CG pretty much. I only ballast in pairs - 2 bars, 4 bars, 6 bars or 8 bars. In that sense it is not very complicated to remember where the ballast goes. It's just a little rustic. The inside of the joiner holes are not uniform sizes so you can't really fit super tight in them.
I don't think you would get a 20mm round ballast tube in the fuselage. Maybe a smaller baudis style rectangle might do it (maybe the 14mm square of Tony's). Full ballast on mine is 1450g (enough for most flying I think). As I say I have been flying distance with 1/2 or 3/4 ballast this season. I even did my best speed with 1/2 ballast.
I don't think the servo is glued in here. I am just having a play.
It's a nice model. You will enjoy it. My settings are a little different to the set up sheet. Those throws are too big for me. I have less differential. I am trying a bit of rudder mix now too. I use aileron>flap mixing too of course (which is not mentioned on the sheet).