All of the Regals I have seen have the spider arrangement. I experimented with blues playing and it sounded pretty good to me. I think I have seen a Samick with a bisquit once and Epiphone makes a wooden one with a choice of bisquit or spider.
Dick. There is no one standard tuning; but there is a standard philosophy and that is to tune to an open chord. Since your fingers are not as free for fretting with a bottleneck on one of them, you want to minimize fretting. Also it is easy to make a barre with the slide, so if your instrument is tuned to a chord, you can get all the other chords up the line.
The most common open tunings are (going from the bass string to the treble):
Open D: DAF#DAD
Open G: DBGDGD
Open C: ECGCGC
Open E: EBG#EBE
Of those the first two then to produce a lower tension than standard and for slide playing would require heavier strings. The second two are higher tension and you should be carefull with heavy strings.
There are variations. For example Open D6 in which the treble string is tuned to b (one tone above the next string down!) Skip James uses D monor: DADFAD which he calls "cross tuning". Open D is often called "Vestapol tuning" and open G is often called "Spanish tuning". Charlie Patton tended toward open G. From watching a video of Brownie McGhee, I think he used open D.