For what it's worth, I've used nothing but mediums (mostly nickel, though often stainless) strings on my Ricks since I took off the factory Maxima flats when I got my first ('76 4000) in 1986.
Mine have the usual amount of tail lift, less than 1/8", and often this is because the body is not perfectly flat front to back, they are hand finished after all.
I've never had a neck issue, ever, of any kind, and I tried using the heaviest, highest tension strings I could find (Rotos) before I knew that they weren't designed (until the 4003) for roundwound strings.
Now I use medium nickels exclusively, stainless go dead too quickly for me.
The RIC string set is 45-55-75-105 and that's what ships on new basses.
The A and D strings are not as high tension as the E and G, so they feel a little weird at first, but if they ship 'em with those strings, then they can certainly handle the tension.
I've seen numerous posts from folks who have used B E A D tuning on Ricks with the lower 4 of a 5 string set, up to a 135 with no ill effects, just rod adjustments needed, naturally.
How's this for neck strength: Jeff R (Ric5) puts a 5th string on a standard 4003 (and adds the 2 extra tail screws for insurance). That's a LOT more tension added than just using heavier strings, and the neck works very well, he even says the bass resonates better that way, and he's been doing this mod for years.
Check out his site for more detailed info.
There have been a few instances where the black tailpieces have bent under string tension to the point of near failure, but that's apparently due to the heat treatment required to give them the black finish.
The standard tail rarely causes serious.
Granted, it's an old (1950s) design and could use a substantial update (reported by the CEO to be in the works), and the functionality is a compromise compared to modern units, but if you don't expect it to be what it can't be and can live with the quirks and compromise, it's fine, IMHO. Once it's set up, how often are you really likely to frig with it?
If you are a constant tweaker and experimenter, then a Rick probably isn't the best fit.
They are what they are.
Some love 'em, others hate 'em, many find them great only for specific things. They are more versatile than they're given credit for being, and are plenty rugged, and very well built, and extremely stable.
I haven't played all of 'em naturally, but mine are totally reliable.
The best bass ever made? Probably not, but for a regular production bass (or guitar) they are easily equal to anything in their price range and even above.
I bought a rebuilt one years ago and installed it, over time, in three Ricks I had, the one pictured above (before I got the HS PU), my '98 4001V63 (I have a recording of that), and one of the two '73 4001s I had, which is now with a friend of mine.
