It all depends on the guitar. With carved top guitars, the height difference along the body can vary significantly compared to a flat-top. You also need to factor in the height of the fretboard above the body. The angle needs to be sufficient to get the strings running over the top of the bridge, taking into account a low action setup which might only have the low E say 1.5mm above the frets at the 12th fret, without the bridge being too low or too high. Fender style bridges are generally lower than Tune-O-Matic styles as the flat Tele/Strat and the height of the fretboard above the body allows for no neck angle being required (or conversely means a lower bridge and no pickup rings are necessary - a Leo Fender cost saver). The body shape of a Les Paul, plus the much higher design of the bridge, means that a neck angle of 3°-5° is required (the actual angle has varied over the years on LPs as construction methods and tolerances varied), though most are around 4°. One reason why the bridge and tailpiece height on them is very adjustable.

From the single pair of mounting holes, you can tell FW is going for a wrapround bridge, which means that it's going to be quite high off the body. so with a (currently) flat top to the guitar, he's going to need a reasonable neck angle.