Sorry for the Ajahns - and I have much much much respect for Thanissaro Bhikkhu - but I don’t think that you have to go as far as the consciousness ayatana (6th Jhana - viz. to leave the space ayatana), to be a stream enterer.
Second/third jhanas (starting with cetaso ekodibhava [transcendence of citta] and ending with sampajano [clearly discerning]) —or— the 12th/13th steps of anapanasati [freeing the mind (vimocayam cittam) and contempling impermanence (aniccanupassi)], would be quite sufficient to do away with sakkāya-diṭṭhi and vicikicchā (undiscerning), I presume.