i have been using an eightarc fusion. for agA i slide across the three bottom right buttons.
the sanwa buttons take very little pressure to get an input, so i have found that the easiest way to get a slide input is to overexaggerate your movement while applying little pressure, so you slide over the tops of the buttons, but then have to realign your hand (if you do not understand i will draw a picture or something). also, tape/bandage your fingers if the slide inputs are hurting.