Welcome to the STD forum.
Going to your last question first: Once a person has HSV of either type, s/he is immune (or at least highly resistant) to ever catching a new infection with the same type, anywhere on the body. If both members of a couple have HSV-1 at any body site, they need take no precautions of any kind to prevent transmission to each other. If this is your situation, then your other questions are pretty much irrelevant.
There are no data on genital to genital HSV-1 transmission, but probably it is rare. First, half of all people (in the US) have HSV-1; for the reasons above, those people aren't at risk at all. Further, most people with genital herpes due to HSV-1 have few recurrent outbreaks (almost half have no recurrences at all, after the initial infection), and asymptomatic viral shedding also is uncommon than for genital HSV-2 infection. To my knowledge, I have never seen a case of genital-to-genital HSV-1 transmission. That doesn't mean it can't happen, undoubtedly it can. But it appears to be rare.
Does suppressive therapy make a difference? Probably not much, and I rarely prescribe suppressive therapy to patients with genital herpes due to HSV-1. But presumably it would further reduce the already miniscule chance of transmission.
Similar questions have been answered many times; entering "genital HSV-1" into this forum's search window comes up with ~1,900 threads. Please scan them if you require more detailed information. A good one is
http://www.medhelp.org/posts/show/969931
Regards-- HHH, MD