I would tech IW next. C1CR1Cover Gallics would be better for dealing with Mansa. IW would also allow you to work that gem mine for more research. If it isn't too late, chop out Stonehenge and let the GP that will pop up in 75 turns build your shrine. Mansa might not get a GP since he seems to like GS (don't we all). If you go the IW route, let some of them get G@ and then whack some barbs for the 1 xp needed for G3. With the free cover promotion they will do nicely for taking a whack at top defenders. The 50% retreat chance works on nonhills as well. And if he has any hill cities then the 25% attack coupled with free cover should be enough.
Next city could be 1NE of the lone mountain peak. First borderpop seals your borders. Then another city 1SW of the gems to claim the 2nd spice and you can use the fishies there to whip GW's.
Waiting for vassalage could mean he vassalizes to someone else for protection.
Next city could be 1NE of the lone mountain peak. First borderpop seals your borders. Then another city 1SW of the gems to claim the 2nd spice and you can use the fishies there to whip GW's.
Waiting for vassalage could mean he vassalizes to someone else for protection.