Hi Jens,
I must also concede to having little 'working' knowledge of the ricasso, and rely more on the observations of those who study the martial aspects of these weapons for that perspective. The material I have discovered and referenced from various sources concerning published reference to both the ricasso and practice of placement of finger around the quillon is simply noted to present established data on the topic. It seems very clear that no conclusions can possibly be drawn on most of this data and those who review it can use it to establish thier own observations. I always hope that someone reading this material might have material that would either support or rebut that which I have cited.
In further thinking on the tulwar it seems important to note characteristics of certain types. The quillons on the tulwar actually seem vestigial and poorly suited for guarding, which agrees with the idea that sword to sword combat with these seemed unlikely. This brings about the forms which have the knucklebow added, a feature which would suggest such sword to sword combat. Were these types mounted with ricassoed blades as well?
I keep coming back to the very presence of the ricasso, if not for the safety of a forefinger, then why was it there? Its presence is pronounced on the Afghan paluoar, which actually does have the drooping quillons that would protect the finger.
Although it seems we have deviated from the original course of this thread somewhat, we actually are still considering the hilt sizes as measured, and the feasibility of looping forefinger outside the area of the crossguard/quillons accounting for the smaller size on some hilts. The mysterious Indian ricasso and its purpose seem very pertinant here and hopefully we can at least review the collective data on it....long way to go yet
All the best,
Jim