There are some variation to the types of stimulants, but you may struggle. My daughter cannot take any of the stimulants without tics. For us Tenex (guanfacine) was an option that we used ofr 1 1/2 years, but then she became so angry and nasty, I had to pull that too.
We are using natural alternatives now with success. I cannot go back to the meds. I have my slightly hyper, sweet kid back. We struggle with focus, but the alternatives are helping so far.
One day at a time.
If your son has tics on one type of stimulant he may have them with another type of stimulant but it's not certain that he will. Some kids can't manage on one stimulant but another may do the trick with minimal tics. Also, sometimes docs add Tenex to the mix to help counteract the side effects of stimulants-one being tics. My son doesn't have tics but he does have other annoying side effects and the Tenex helps those.
Is he on the Seroquel for bipolar, trouble sleeping? I was just wondering if that has any effect on the meds or not. I'm not that familiar with it.
Also, even if your son cannot take stimulants, there's still Straterra or he could try Tenex by itself.
Good luck and I hope things get better for your little guy!
I think different stimulants can cause different reactions. My daughter has tics from time to time with stimulants. She takes tenex for this and also to help her be a little more even keel. We found that on focalin xr the tics were far worse than on Ritalin LA or Concerta. My son is on Seroquel for his ADHD, to calm him down, and it worked up
Strattera seems to help those who are not impulsive or hyper, just the more inattientive type.
I have experience with concerta and tenex as a combo. DS tried addrerall xr and strattera ( to be used along with concerta at the time) but both of these the side effects were very negative for him.
We have been very happy for the past 5 years with concerta and tenex. It gets us through school, homework, he eats, and sleeps.
As far as tics go, he clears his throat. Prescribing doctor believes it is a tic, but it goes away. He does have phlem, however. Maybe the pill causes that in his throat, not sure. 
I hope you find something that is successful for him.
BETHANN40149.3455208333Just met with the doctor today and she has prescribed some Tenex (she wasI agree - each of the stimulants has a unique effect. My daughter had tic reactions to 3 or 4 meds. Because they are all in similar families, for now, we are not trying anything new. Her reactions were pretty severe in some cases - Concerta was the worst, in her case. Focalin was mild, Vyvanse, the tics started after a couple of days and were worsening.
Unfortunately it is trial and error for the most part.
Just be aware that Tenex has to build up in the system before you see any results. They say up to 4 weeks. We started seeing positive results within a few days but didn't see the full effect until about 2 weeks. Good luck!