Hi Doug.
I've done the test and to my eye the arm is higher at the headshell end of the arm but it's not quite that simple. As the arm comes out of the counterweight (shiny silver) assembly, it is a seperate piece of metal and slightly different in colour. At the start of that part of the arm (coming from the counterweight end) the first 2 inches are straight, but then the arm gradually rises slightly (1.5mm ish perhaps) until about halfway,then stays level for an inch or two, then just drops off slightly (possibly 1mm or less) as it heads towards the headshell.
I cannot see any sort of spacer that has been added to adjust the height of the arm (having viewed many r200 arms that have been raised i can clearly see those spacers so pretty adamant mine isn't raised).
I've looked through a lot of forums regarding the r200 arm, and i came across one that suggested that having the r200 arm raising slightly at the headshell due to a different non Rega cartridge isn't detrimental (annoyingly i can't re find the link to it to show you, but pretty sure the quote was from someone high up at Rega).
Apart from my sibilance problem, the sound from my turntable is very pleasing, so i can't believe sound quality is suffering, but i wouldn't want to be damaging my (new) records ????
Going back to the sibilance issues, i have added the new power supply to the Firebottle phono amp (which i found out has mullard valves in it,for what thats worth!) and i can report that the sibilance seemed worse than when played through my Denon phono stage. Funnily enough it also felt like some bass was too bassy, which i hadn't noticed before, so i've cut the firebottle out of the set up again. I would add that i do like the sound from the firebottle with a certain type of music - predominently male vocaists with a stripped down vibe (the newer Neil Diamond or Johnny Cash recordings by Rick Rubin or a laid back Frank Sinatra LP 'In the wee small hours of the morning').
Just to confuse things more i found the source of the feedback issue (heard most through headphones before records start but also through speakers...when volume dialed to abovew 85%). turns out it's the tonearm so must be an earthing problem as it changes when touched.
Question to everyone is whether that is a normal thing (the tonearm hum) given that i'm new to turntables and it's only audible when music isn't playing and when turned to very high volume (or highish volume through headphones).
As stated previously, the overall sound is good, and almost always better/more involving than digital rips (even hi res stuff) so at the level i'm at (i.e AVR, £400 ish speaker, £300 ish headphones and £250 2nd hand turntable) i wonder whether i should just get on with enjoying it....but then you always wonder 'can i make it sound better'