Much as I really love TremoloVerb (it's actually become one of my faves on Space now! ) – its reverb algo can't really give you that wonderfully surf-y sproingggg-y tone that the Spring algo can.
Considering how amazingly good the Spring algo's tremolo sounds – I definitely agree that the option to be able to position it either pre- or post-reverb would be a great possible update for Space!
Try the Tremoverb algorithm in Space. That puts the reverb (first) through a tremolo (second). Sounds like what you're looking for…