There's a topic on android/DIY, can't remember if it's the one i followed but it did work on ios aswell.
Ex: with my driver club
show the club stats
power 234 / acc 29 / top 50 / back 48 / curl 30 / guide 2.8
Pick 3 values we will search in iGG (like power/top/curl), 4th is the ball guide:
search number
(f32) 234
Toggle switch top right, nearby
(f32) 50
nearby
(f32) 30
nearby
(f32) 2.8
Toggle switch top right, number
(f32) 2.8
you should now have a couple of numbers around 2.8. Find one that is 2.8 and change it to 5, go back to game, close & reopen club info, if ball guide is not changed to 5 repeat process (find another 2.8 & change it to 5) until you find the good one. Once found, save the adress (long press). Now go to memory tab and press goto on top right. 1st line is ball guide, save the 3 adresses just under like driver1 driver2 driver3. Now you can change any of those 3 values from 0-32. Change the values to like 28, 27 & 26, back to game, close and reopen club info and u'll notice that ur club have now abilities: POWER 3 / SPIN 3 / WIND 3 in addition with full ball guide. You can do this with all ur clubs. You can stack power (28,28,28).