I have played slide for a long time. I use a Dunlop glass slide on my 2nd finger, because I have played in a lot of trios and it allows me to still play barre chords with fingers 1, 3 and 4. I started out with what I heard was the Lowell George tuning, tuning the high E string down to D to make the 4 highest strings into a G chord. I would tune that string down on tunes where I played slide, then tune it back for conventional playing at the gig, except when I forgot to tune it back, which was often. So then I learned to play slide with conventional tuning, which is awkward but it can be done. To get a minor third you have to angle the slide between the B and G strings, which takes practice. More recently I picked up an Ibanez GAX70 for peanuts at a pawn shop, which I now use exclusively for slide. I tune it to an open E chord and I am using .13 strings for both the B and E strings to get a thicker tone on the high notes.