No, I wouldn''t use the expensive thread unless you won''t been around a sewing machine in 5-8 yrs to do a restitch. However, I wouldn''t use the cheap polyester thread from your local sewing machine center either. Buy BONDED polyester (dacron) thread for your work. Sailrite has it at high costs but in small spools for home projects. You may find it locally at a commercial sewing supply shop for 1/2 Sailrite''s price. Choosing the right thread and needle will eliminate most of the frustration in getting a home machine''s tension adjuster to cooperate for good stitches.
The home machine you have will determine thread and needle sizes. To be safe I''d suggest a V69 thread and #16 needle. If your machine is an older all "steel gear" type it will probably handle larger V92 thread and a #20 needle. The higher the number the bigger it is. I have two home machines and two commercial machines. All work on the same thread/needle combos with Sunbrella.
In case you don''t know, your local marine canvas shop probably uses V69 on lightweight material and V92 or V138 thread on Sunbrella type. I wouldn''t worry about the reduced size of V69, especially when restitching because you still have the original thread to help.