I've ordered 60 grit dronco jet flap discs, a wise choice?
Excellent choice, the best ones I've ever used. You should find them more precise as the plastic backing is stiffer & keeps the disc cooler, meaning they last longer.
I find that the old fashioned thick 3mm cutting discs are great for tidying welds or worn down 2mm discs off a 9" grinder. More precise than a grinding disc but stronger than a slitting disc.