Flying saucers aren't a good wheel anyways
They're certainly no replacement for an upright wheel,at the very least.Getting an upright wheel as soon as possible is extremely important,as they actually allow for a natural running position unlike flying saucers which cause side arching and are nowhere near a natural running position.Upright wheels also take up much less room which is a definite bonus,since you can add far better enrichment like foraging areas for example!
You can always expand the bin eventually by direct attachment of several bins(in fact,it can go above and beyond the Detolf but be more mobile!).As long as you have secure attachment,use appropriately sized mesh,and don't attach with tubes(or any other way that is not direct,meaning large sections of walls only,no tiny holes and such!) this is a great choice for housing Syrians,as it can be expanded as needed unlike premade cages or something like the Detolf which would not be easy to expand(possible,but extremely heavy and impractical in sizing and shape).