i had purchased several different cascade rod blanks last year and am now finally getting to building them.....this is my first attempt at saltwater fly rods and am looking to order parts to build them with. How is the best way to figure the sizes for the parts (reel seat/grips/tips)?

I have a:

Cascade RX8 (9' 2pc 12/13 wt)
Cascade RX7 (9' 4pc 9wt)
Cascade RX7 (8'6" 2pc 7wt)

should i just measure the diameters and go from there?...any assistance would be appreciated.

thank you

Yes, measure the diameters and go from there.

On the reel seat, however, select the seat that fits your hand best, and then shim to fit the rod blank.

..............

Josh,
On the saltwater flyrods you just need to know the blanks OD at the butt and buy a reelseat that has a larger ID. Your hand size isn't important as you'll not grasp the reelseat like you do spinning rods. The Rainshadow site will get you pretty close as to butt dia. as Cascade used to make their blanks. If it looks close on reelseat diameters I'd for sure measure. The all aluminum reelseats usually used on salt rods makes selection much easier as they are usually pretty large in ID.