Indeed you are
Assuming you're leading off with the bound spells, your opponent won't dare throw one die with his LV4, because (just like with casting) a roll of 1 or 2 always fails, breaking the wizard's concentration and preventing him from making any more dispel attempts (or using scrolls, etc.)
So, if they brought a second caster -- most do -- they can probably afford to be a little more pushy with trying the one die, as it doesn't hurt as bad if he breaks concentration -- except that the dispel scroll is usually on the L2 and failing a dispel roll will take it off the table for the round, and they'll have to be a little more conservative with the L4 as they won't have backup.
But let's ignore that and assume they make all the dispel rolls,
and they're successful in dispelling your casts. The end result is you lost a power die, and they lost a dispel die. That's great; if you keep that up, eventually you will have "some" power dice, and they will have "none" dispel dice, and you didn't even have to waste a good spell drawing out those dispel dice!
Even if they don't ever fail any dispel rolls and dispel every solar engine, that can turn a 7PD/4DD phase into a 5PD/1DD phase, which is a lot better for getting spells off. ("Well that would have happened anyway!" Yes, but you would have had to cast a good spell and given them the opportunity to dispel it, instead of dispelling some random bound spell.)
But it's even better, because they aren't always going to risk a 33% chance of shutting down a wizard for that phase, so if they want to dispel it, they'll throw 2DD, which is pretty amazing.
So why don't they let it go off? See, on the offense, you're seeing the bad results, the d3 S3 (lol) or the d4 S4, but your opponent can't afford to think like that. There's a 50% chance that the spell will land
at least 2d6 S5, which is a pretty nice hit and can absolutely wreck a lot of units. No one is going to risk that without thinking about it.
The end result is you either a) shut down a caster, b) waste their dispel die, or c) get off a really powerful nuke, or maybe even some combination of the three.
Now, as a caveat, this kind of trickle-cast strategy works best when you have cheap spells to follow up with to take advantage of the reduced PD vs. no DD. I've had better luck running solar engines with wandering deliberations, and not so much with high magic. Still experimenting, though!