If an inventory of extreme potions takes ~14 seconds to make 14 and there are 5 types of extremes to make and overloads take 4-5 seconds per inventory... that would mean that in 1 min and 30 seconds you get 8,800 herb xp. Since herbs and secondaries can be gathered on g.e. that means that the time taken is 0.
So herb = 8,800 xp/1.5min or 352k/hr.
Assuming that you gather blue charms at glacors and are decent at killing them, 1 kill (correct me if I'm wrong) takes 1.5 mins/3 charms (if a blue charm drop were to occur, let's assume it's 100%). That would give you 120 blue charms per hour at a 100% drop rate. Assuming you can make geyser titans and each bank trip takes 30 seconds from bank -> obelisk -> restock, you will make 783.2 xp per titan at 25/trip which comes to 19,580 per trip. At 2 charms gathered per minute it will take you 12.5 minutes for 25 charms for 1 trip +30 seconds for the trip, so 13 minutes/25 charms. This means that (19,580/13)*60 would be the amount of exp you can gain in one hour of total summoning time.
This equals 90,369.2 xp/hr with charms taken into account.
At 1 kill/1.5 mins that means a crimson charm and a blue charm every 1.5 minutes. 40 kills per hour so 40 crimsons and 40 blue charms per hour. 40 crimsons = 17,408 xp, 40 blues = 31,328. 30 seconds per run from bank -> obelisk -> restock = 2 mins to use all charms. 1 hour and 2 minutes of time = 47,163 exp/hour (60(total/62)).
Why is summoning capped when other "frontloader" skills like herblore, fletching and the like aren't?