Bought 6 & lived 20 yrs where Cali rain originates Washington State. Liked the look/feel so much first 5 yrs keep hardtop on year round, now on Sept/Oct off Mar/April. Been caught in major downpours Northwest Cascades to Rockies several times where windblown rain seems to be at 90 degree angle little to no rain enters the cockpit. Appearance wise TR6 Factory Hardtop 2nd to none, like windscreen post to post, is wider than window to window and as mentioned in the previous reply the metal lip/rain gutter catches & channels h20 to rear.
Note: Have encountered a little cockpit mist generated by 3 trailer/train trucks in Oregon. Even during washing unless windows hit by horizontal blast of h20 in 1/4 gap area between top of window & hardtop (near hardtop window post) very little to none enters cockpit. Some owners have removed door panels, adjusted window glass on track to eliminate this small gap, happy with mine as it simulates a little cabin refresh airflow