Some folks would omit the spindle roughing gouge and use their bowl gouge to rough our spindle blanks.
I usually omit the spindle roughing gouge and instead almost always take a square blank to round with the skew. I think it's easier and is faster to make a cleaner surface. It's important, of course, to not use a skew that's too narrow or risk a splintery mess! A 1" to 1-1/4" skew is great even for fat spindles, 1/2" fine for thinner spindles.
A rare but potential problem is with some particularly brittle wood and grain orientation - it's possible to start a split which can continue down the blank, getting deeper until it splits off a chunk (or even breaks the blank into two pieces!) Of course, this can happen with the spindle rouging gouge or bowl gouge as well! I do examine the blank ahead of time for problem grain.
However, two things can prevent an unwanted split. One is the usual method: start roughing very close to one end with each new pass a bit further away from that end. Start each pass by entering the wood with a cove-like curve then flatten that when heading towards that end of the blank. Then do the same thing in the other direction on the other end until meeting close to the middle.
Another little trick works to prevent splits on splintery wood - start by making a series of quick V grooves down the blank, cutting deep enough so the bottom of the Vs are close to the final diameter. If a split does start it can't get past the next V. As the corners are cut away, the Vs can be deepened a bit more, but that's usually not needed since with each pass there is increasingly more supporting wood.
If the square blank is long and thin, say 1/2" in diameter and maybe 12" or longer, the backside must be supported with the left hand just like a thin spindle. This might sound unreasonable and possibly painful but it's not - the support needed is very light and I always turn thin spindles a high speed. Securing the drive end in a chuck makes it easier still.
All this sounds like extra trouble but I think it is quicker and easier than using the spindle roughing gouge. Obvious if watching in person. I should make a short video.
The end result is the whole blank goes from square to a completely smooth cylinder with the skew. Note: I have beginners stick with slow cuts with the roughing gouge.
As for the roughing gouge, I mostly use the Thompson 5/8" with relatively thin spindles, not necessarily for cutting off corners but more for quick shaping of curves - especially good for shallow coves. Then refine those with the skew. Another plus for the Thompson is the "U" shape with a straight, vertical edge on both sides - in use the tool can be rotated during the cut to use those edges exactly like a skew. The 5/8" diameter is easy to hold so I don't mount it in a handle. That might be good to put in the video too.
JKJ