You can run the 7/8. You may have to add a little bit more charge than you would with the 3/4, but that is the same with added length beyond the factory charged 15 ft.
Sorry Jeff.....My BadI can't seem to find any info on the: CAPF3642B6
They have C6 and D6 but no B6.
Do you have a datasheet different then the one on the website?