I have little experience with local registered mail, mainly using Registered Post International which is Paypal's minimum postage method to qualify for seller (or sender) protection, as the lodgment for these is done in triplicate before being stamped by the PO, and your copy of the multiple receipts is your proof of sending which satisfies Paypal's requirement perfectly.
As I understand it, you can also buy pre-paid rolls of registered post stickers, but I don't believe these are suitable for Paypal because the only receipt given by the PO is the standard PO postcode receipt, which only proves that you sent an item to that postcode, and not necessarily that address.
However, even for local use in Australia, you can still use the RP lodgement papers in triplicate, and your copy of the stamped paperwork will then definitely cover you against a Paypal claim for INR.
Problem is, for items under $50 or so, it's just not cost effective to use registered mail so unless you're losing a lot of items in the post, put the money for registered post into a jar to use in the event that a parcel goes missing, and I'll bet that in a year, your jar will be nearly full. 😉
Also, you cannot enforce the compulsory use of registered post for items over $50 as doing so breaches policy. If you feel you absolutely need to send it registered, do so out of your own pocket as the buyer won't select it themselves.
Also, express post satchels aren't covered by Paypal unless you use the 5Kg satchel, or post your express item as a parcel and use the lodgement form in triplicate, so once again you have stamped proof of sending. Also, you may need to alter your T&Cs because I believe that express post parcels (but not satchels) require a signature upon delivery.
Realistically, your items are not expensive and I see no need to bother with registered or even express, and would simply use click and send, perhaps with SOD on your dearer items (but at your expense if it's free post).
