I can't help with your exact question but I hate to see threads go unanswered. All I can suggest is try it out. Personally, I think that sounds about perfect. I run 28t 48p in mine and the physical pinion sizes are the same I believe. I don't know about the spur, but should be good to try. Just monitor temps as always.
LST2 E BL, Losi 8ight RX8/2150kv,
TC3 BL, Losi XXXSCT BL