Rear AC Hose Question/s

[WannaBe68]

Was able to get my hands on, what looks like a very nice, original Harrison rear ac evaporator unit. Thanks Randy500!

The Vintage Air Gen lV SureFit system I had installed a few weeks ago uses #6 and #8 hoses...which seems to mean I will need to use those sizes, for the rear unit, to be able to tie into the existing Gen lV system.

Question is --- The original hoses were 3/8th and 5/8th ID, but I can't use that size because of the Vintage Air system. The Harrison unit's exit and entry pipes fits the 3/8th and 5/8th sizes. If I run the Vintage Air #6 and #8 hoses all the way to the back is the there a way to connect them to the entry and exit pipes of the evaporator? A step fitting or connector or something?

Thanks in advance!