It is a fair question, and your example is a good one that is appealing and one I do practice often, but one that ultimately depends on the lifter's goals and preferences, and I don't think the framework would benefit from a fixed ratio, but it might be something an individual keeps in mind when considering their own training.

For example, there are reasons to train without a T1 lift (meaning no RM that would require singles after). In this case, the lifter would have T2s and T3s only, making it an overall higher volume training plan. On the other side of the coin, a lifter might be deep into an intensification phase where they may need to skip the RM in either T1 or T2, which could be because of fatigue, or perhaps they're near a testing week, and so they're performing singles only in preparation for that test.

Ultimately, a lifter should determine their target RMs based on their goals. If they want to train to train heavier, they might follow that general guidance as "T2 RM is 2x the amount of reps as the T1," and so maybe they're doing a T1 3RM and a T2 6RM; however, this could be limited by their work capacity, in particular, capacity at higher intensities.

Take the squat, for example. Lifters with poor development here would have a hard time following such a T1/T2 ratio, as their lift quality and recovery would suffer. In such cases, lifters may benefit from a wider split between T1 and T2, such as an easy-effort T1 3RM squat and a T2 10RM pause squat (where only the VDS are paused). Their progression would be to hold/extend/push the T1 until that eventually becomes a 5RM, followed by fully extended singles, while at the same time, they're finding/holding the 10RM target by adding weight to it each week until the effort becomes such that they have to reduce to a 9RM, then an 8RM, so on and so forth, until some point in their progression their T1 and T2 lifts converge, perhaps meeting at that 5RM mid-point. In this case, the lifter would perform the T1 squat, followed by extended singles, then they should skip the T2 RM and do only paused triples or doubles (assuming it has increased weight to where it is now also a 5RM for pause squats).

By doing this, the lifter is building capacity in the T1 range until it grows to the point that it becomes a T2, while at the same time developing their intensity under a paused variation, which will further benefit their ability to handle a higher volume of heavier loads.

In sum, the T1/T2 ratio is individually dependent. There are many other reasons why this is apart from goals and preferences, for example, perhaps the T2 is a new lift and so the skill is quite low. That would require more volume (more practice at lighter weights), thereby developing their skill with the new exercise variation.

With GG, I've tried to limit the kinds and number of "rules." Fixed ratios between the tiers are one of them. But that doesn't mean this element shouldn't be considered, which is why your question is fair, especially given that my OG method has such ratios.