Felipe Massa said the radical front and rear wings tested by Williams this week in Barcelona have helped the team decide which development direction to take with both this year's car and 2017's.
Williams tested extra winglets on its rear wing and supports on the front wing as it went experimental over the two days of this week's in-season test. The wing would be illegal under the regulations but appears to be designed to simulate a shift in the centre of aero pressure, with Massa saying it helped Williams to better understand the balance of the car.
"For sure this wing is not making the car quicker!" Massa said. "This wing is there for us to understand some things about the balance of the car, in view of some things we're hoping to have to make the car better, to develop the car. But I think it was interesting for us to try it.
"It was a day totally devoted to the aero tests we were doing for the future. Hopefully not for a too distant future, hopefully for earlier than we had even hoped for and we understood a lot of things that are important to help us develop the current car quicker, to make it better, especially in the type of corners we know we're losing out to some of the other teams.
"No doubt it was an important day for the engineers and also for me, to be able to give very precise feedback of what I was feeling from inside the cockpit, both in low and high-speed corners. These two days were certainly aimed more at the engineers' work than to ours, of course."
Williams has struggled with performance in slow-speed corners in recent years and Massa said the work this week had helped it find a new direction.
"The feeling was good, yes, but we tried a lot of things, a lot. Some of them didn't work, but the general feeling was very positive and we found things that were important to lead us in the direction we think we should be heading into to develop this car."