Different airlines have different standards regarding the application of RW time to their required FW totals. Many airlines give no credit at all. You'll need to look at each airline you apply to individually to see what their policy is.

Skywest for example always allowed some helo time but required about 750 FW (+500 RW) as a minimum. They recently changed that to allow any amount of RW plus 250 FW totaling 1500 (ie ATP mins) so you could apply there as soon as you get 1500. Actually you could apply now and they'd hire you and give you a class date after you hit 1500.