Well, let‘s take a look at your situation. What level are your athletes or clients at? New athletes or clients probably would not benefit from percentages as much as more advanced clients, as they need to learn how to perform the lift correctly first and foremost. Second, a new client will adapt to the exercise so fast that by the next time you perform the exercise, their 1 rep max may be out of date and thus their percentages would be incorrect (if they used to bench 100lbs, but after 2 workouts they can bench 110lbs, that 60% you have them working out as now too low to cause the adaptation you are looking for).
The regular payments you have so far found will form the core of your household budget. You can now turn those into a formal list, either on paper or on a spreadsheet, and put the amounts into the next column, with a heading notifying the month. Before moving on to the next phase, add a further 11 columns on the paper or spreadsheet, with the headings changed to appropriate months until you have a column for each calendar month for a year. I have prepared an example budget spreadsheet to help you.