I understand - as I regularly attend an Indult Mass as well but on the occasions when I attend the N. O. Mass, I try to be obedient to the rubics outlined in the GIRM. “when in Rome”, etc. You know when we have visitors to the Indult Mass, we expect them to obey the rubics outlined in the 1962 Missal - i.e. kneel for communion and receive only on the tongue.
I know it is sometimes difficult to do this but I try to remember that what the Lord loves his people to be obedient and bowing is also a sign of reverence. This is what I do before I receive and I still have choices in that I can receive on the tongue and have the option to stand, kneel or sit after I receive.
It is good that you are questioning which is the correct method so you can adhere to that when you do attend an N.O. Mass and readin RS and the GIRM can help you with this. We cannot depend on doin what others around us do because in some cases they are the reasons why the new RS instructions were issued. Think of it that way also. One reason the N.O. Masses are so full of abuse is that so many people did their own thing.
Each Mass (1962 and 1970 missals) have explicit instructions in some areas and these should be followed. The 1970 does give us some choices in some areas and we can make those choices when allowed. (i.e. we can still receive on the tongue, we can receive only one species if we wish and we can kneel after communion if that is our choice).
If we wish to have the Indult Mass, we must not make it divisive but unitive by abiding by the rules in both cases and know that regardless of our liturgical preferences, we are, above all CATHOLICS.