i think you'll be sedated. you could take both of these at the exact dosages you have with little to no risk. seroquel at that dose is moderately sedating and the phenobarbital at 60 milligrams would be mildly sedating.
now if you were talking about having 60 as in quantity then you stick to dosages of both that are under 100 milligrams. phenobarbital has a super long half life waiting even two days apart can cause an overdose if you take enough. serouquel is just an anti-psychotic, but it really knocks you out. don't take anymore than 50-100 milligrams.
also, don't expect anything particularly synergistic. they're both shit drugs unless you want them to pass out.