Good question... I'm not sure, there are minor differences in their characteristics, but nothing that would indicate anything major, other than EL being EU design and the other one US (or one is a copy of the other one...). I did not hear 6CA7 in i34, so I may be missing something.
For i34 I recommend JJ E34L (those come with the amp). And specifically cannot recommend EH EL34. Everything in between may be hit or miss.... as is always the case with tube rolling....
Even though i34 runs the tubes very conservatively, you still need them in good condition to get maximum performance. Using weaker tubes negates benefits of component derating.