AN SS brake lines

[biohazardbill]

Setup is front disc, rear drum.

Went to Summit to get SS brake lines and fittings. Sales person A gets me setup with -4 an line and conversion fittings. Went back a little while later as the fittings I got (suggested by salesman) for the caliper would interfere with the airbag. Salesman B could not find banjo fittings that would work and suggested I go with -3 line as that is more common to use.

So which is right? Should I use -3 an or -4 an lines for the front? Since the rear is a larger line what should I use for the rear?

Thanks for any insight.