Set up shoot, chimp, re-set,re-shoot,chimp,re-set,re-sshoot,re-chimp. What could be done without firing a single frame requires a lot of steps, and is only good on static subjects that do not move.
My feeling is that the exact placement of catchlights and shadows is the secret to good studio lighting.
As far as your equipment Tirediron, M90's have three low-powered modeling lights, MW3U's have the 100 Watt quartz lamp, and M11's have a 150 Watt quartz lamp that throws a fairly bright light that has a definite hot spot, a dot, right jn the center of the beam, while Black Line heads have very powerful 250 Watt quart lamps that are super-easy to see by. I use the modeling lights to see where my catchlights are, and where my nose and under-chin shadows fall. The smaller the modifier, the easier it is to see the effects of minor light placement variations; the bigger, and mushier the light modifier, the tougher it is to discern minor movement effects.
Let's talk about a simple, two-light, key light plus fill light setup. I used to work in a portrait studio where the critical factor was setting the precisely right height and angle for the nose shadow, and the key is and always has been to literally MOVE the light through an arc on the floor, to actually determine visually, exactly how the light interacts with the subject's face and body; that is what is lost when using speedlights--there is literally ZERO opportunity to visually observe a myriad of light placements when using a speedlight. The ability to move the light and to literally SEE the effect of multiple light placements is utterly lost when using a speedlight. Instead, the speedlight user takes a guess at the best placement.
Secondly, when shooting with a fill light shooting straight ahead, from camera position, in the classic on-axis fill light placement, when the main light is of the same intensity, but closer, it's easy to visually SEE how moving the main light farther or closer changes the main to fill relationship, as well as to literally see the dual catchlights. I'm used to this two lights, equal power, one at 8 feet, the other at 11 feet (to get a 3:1 lighting ratio automatically) way of working. Two lights of identical power and type at 2.8 and 4 feet; or 4 and 5.6 feet; or 5.6 and 8 feet; or 8 and 11 feet, create a beautifully ratioed light. Notice the way the f/stop scale also works with distance? Mathematics and science are amazing things!
Again, I think for the BEGINNER, the ability to literally see what the lights are doing, continuously, is a huge advantage in learning how to best set the lights up. Modeling lights give a constant, continuous, immediate feedback loop. Shoot/chimp/re-set/re-shoot,re-chimp is an entirely different approach.