This should work for the default UI if the mod is still based off it.
Code:
/run local s,t=0,{"ActionButton","MultiBarBottomLeftButton","MultiBarBottomRightButton"};=for i,j in ipairs(t) for k=2,12 do local b=_G[j..k];local p,f,r=b:GetPoint(1);b:SetPoint(p,f,r,s,0);end end
/run local s,t=0,{"MultiBarLeftButton","MultiBarRightButton"};=for i,j in ipairs(t) for k=2,12 do local b=_G[j..k];local p,f,r=b:GetPoint(1);b:SetPoint(p,f,r,0,-s);end end
Combined, these break the 255 character limit on macros, so they were split into horizontal and vertical macros respectively. If you want to adjust the spacing, go ahead and change the value of the local
s. Increasing the value gives more spacing, decreasing will give less and can overlap buttons.
There's another problem that rises from this, the buttons will move toward the left or up depending on bar orientation.