Scott Catalogue India Feduatory Question

So for Travancore, Scott Type A4, 3ch stamp... Can someone tell me the difference between O30 and O31? They can both have the same perf, the same wmk and color(purple). The O31 does have (R) next to it, but the column head overprint example already states they can be either black or red already.... so whats the difference? Also, im struggling with whats an inverted "O". Can anyone post 1 overprint with regular O and 1 with inverted? I've seen a couple of posts but I cant tell. tks!

The series can include stamps opt in Red or Black
(R) determines that stamp in the series is opt in Red.

Inverted "O"
SG#O56c 1933

Inverted "S"
SGO#4b 1921

The Shankha Bhasam, the Sacred left turning Conch
Shown on the Travancore stamps and Watermarks
Normal Left, and the Laxmi (Lakshmi) Conch Right.

One really needs Stanley Gibbons with these.

Scott has only 3 different types of Opts on the Type A4

Note: on the O31, the distance between "O" and "SS" is longer. (Non equilateral triangle)

I think I have them as..

Note:
Any official stamp after 1920 that appears with tinted paper, KEEP!
These stamps were issued without gum, and the stain comes from private adhesive.

I have yet to see any.

Tks rod for all the helpful info. Much appreciated. If I may, to make sure im reading this correctly ask a few more before I jump back into this today. once again on the scott catalogue format

1) where I have circled, top of column, its NOT saying that all overprints from there down are either red or black (LIKE THEIR TYPICAL LISTING CHANGE IN BOLD) , but is just an example for the overprint type?
2) the difference in the listings is that, for instance O31 only comes in red overprint, hence the (R) and O30 only black overprint?



Hope im not confusing the question her, but heres the example of the listing type change...



And thank again the inverted O ex.. The N's and S's are much esier I think. Its hard for me to see the difference in the O's. haha. I hope the day gets better - when I was looking up the example to list here, the catalogue pages slipped out my hand closing shut all at once and blowing all my sorted stamps to the floor. agh....

Stamps4Life, regarding overprint color in Scott - the (R) denotes a red overprint; no designation denotes a black overprint.

tks for the confirm

If you are serious about Indian States, you need to use the Gibbons catalogues.

In my opinion, Rod's illustration of an inverted 'O' is incorrect. That one appears normal to me.

Inverted 'O's are much more displaced, such as this one (I believe this is SG O59c).

(Image from Jiri Cerny's collection):

Hmm, thanks
I'll take that on notice,
I thought I had mine confirmed by Tony Mac,
I may be wrong, my memory was some O's were shaped to indicate orientation. I'll look into it.

Thank you for the heads up.