Grading Guidelines for Reel-to-Reel Tape

Anyone out there know if grading guidelines have been set down for reel to reel tapes? If so can you please point me/us to those grading guidelines.

Doing a web search you can find vinyl grading guidelines, but none for reel to reel...

None that I know of, some are selling R2R media at crazy prices without even play testing.

But R2R tapes are so hot right now they are getting away with murder on pricing!
You think so? 

Like what are some examples?

71/2 ips tapes if in good condition can boarder on a spiritual experience. Can’t put a price on
Nothing I agree with at all on r2r pricing but just take a look on eBay at some examples.

$200 to $500 is not uncommon for "in-demand tapes".

And they are selling.... Crazy but true.
First category of most desirable pre-recorded reels:
'70s-era, 7 1/2IPS Rock near the end of the format's consumer popularity: ESPECIALLY THE TITLES "MAGTEC/STEREOTAPE" DUPLICATED FOR WARNER BROS./REPRISE/ATLANTIC AS WELL AS FOR RCA (ex: Led Zeppelin up through "Houses of the Holy", Fleetwood Mac's "Rumours", Neil Young, Doobie Brothers, Stones up through "It's Only Rock and Roll", Bowie, Elvis, Lou Reed, Nilsson) AND: THE AMPEX 7 1/2 Capitol Beatles albums plus, THE QUADRAPHONIC MIXED MOODY BLUES ALBUMS.

Second category:
1956-1960 RCA/MERCURY/CAPITOL/and COLUMBIA TWO-TRACK Classical and Jazz titles.

Either really late era ('77-'84) tapes from Columbia Record Club (catalogged as "CRC"; even if the Rock titles seem unique to the format: THEY ARE ALL HISSY 3 3/4IPS GARBAGE dubbed, most likely by then, from the same masters wrongly eq'ed for cassette and copied at 120IPS)


Pre-1968, 3 3/4IPS, Rock made by Ampex or Capitol on brittle ACETATE-base tape.  THAT was how 3 3/4IPS tapes were often as much as $2 CHEAPER ($6.95 vs. $8.95 for a 7 1/2 title during the '60s).  Only after 1968 did they change to polyester base across the board.  However, for example: the first issue Capitol 3 3/4 Sgt. Pepper on brittle red acetate IS JUST NOT WORTH somebody wanting $200 for it (vs. the 7 1/2IPS 1970 Ampex reissue Ken Kessler swears by AND, better yet: the 1969 Japan Toshiba 7 1/2 copy I swear by).