I’ve heard that the ICRSS uses the pre-55/6 Holy Week.
These are the two rubrics
Pre-1955/6
In reversione Processionis, duo vel quatuor Cantores intrant in ecclesiam, et clauso ostio, stantes versa facie ad Processionem, incipiunt V. Gloria, laus, et decantant duos primos versus. Sacerdos vero, cum aliis extra ecclesiam, repetit eosdem.
Deinde, qui sunt intus, cantant alios versus sequentes: vel omnes vel partem, prout videbitur: et, qui sunt extra, ad quoslibet duos versus respondent: Gloria, laus, sicut a principio V…Gloria, laus et honor, etc.
In the return of the Procession, two or four Cantors enter the church, and the door having been closed, standing facing the Procession begin the V. Glory, laud and chant the first two verses. And the Priest, with the others outside the church, repeat the same.
Then those who are within, chant the other following verses, either all, or part, as is desirable: and those who are outside, at each two verses respond Glory, laud as at the beginning V…Glory, laud and honour, etc.
Revised Holy Week
Progrediente processione, cantatur sequens hymnus, populo, si fieri potest, duos primos versus continuo repetente, ut infra notatur. …HYMNUS AD CHRISTUM REGEM…Gloria, laus et honor, etc.
The procession proceeding, the following hymn is chanted, with the people, if it can be done, continually repeating the first two verses, as noted below….HYMN TO CHRIST THE KING…Glory, laud and honour, etc.