Guaranteed on hit:
HS~TP, 31, JIK~TP, dash 22~TKP - 38%
HS~TP, 31, JIK~TP, dash 22~Xray - 50%
Herp, derp, after Teleport hits standing opponent Ermac doesn't have guaranteed 31~Lift, the opp can block any string you throw out, TP grants only safejump (just like Scorpion's TP). Hitting airborne enemy with timed HS~TP gives a juggle of 36% (AA TP, j.K~TP, d1~Lift ff b12f1 ff Push).
But IMO the whole discussion is kinda useless - Hover slam doesn't lead to any decent mind games, only really retarded player will fall to HS~TP trap more than twice (even if it is his first contact against Ermac).Additionally, when Hover slam hits we're negative on frames :| If you want to build meter with Hover slam~cancel it'll take about second (around 60 frames) to perform it - you could do two instaAirBlasts in that time. Buffering after blocked strings? Use Force Blast, it builds the same amount of meter, gives 2% of chip and is relatively safer.
b114~Hover Slam~AirBlast near wall? Yes, it could work, but only on standing opponent. What if he's crouch blocking? He'll uppercut the shit out of 'Mac...
You can also do safe Hover Slam cancel on opponent's fullscreen knockdown (i.e after juggle ended with Force Push) but again - what for? You could just do iAB which'll come out faster in terms of building meter, do Fireball to check them standing up or Teleport right near them to start wakeup mindgames - all of these are better than hovering.
The only situation when Hover slam is really safe and guaranteed is Ex Hover slam after hit 312 - opp cannot jump out of it so we get guaranteed 8%, but... 312 gives us safe jump opportunity, j.P b114~ExForceBlast uses also 1 meter, but grants us 11% of chip, without meter 9% (and 45% if the enemy opp finds that he doesn't feel like holding block
).
TL;DR: It's fun to trololo with Buttslamming, but on high level play if you wanna live, Don't. Use. That.