Welcome to Knitting Paradise, Shona!
If you want to make a "a small child's cardigan" but are using yarn half the thickness ... the result done on the same size needles as in the pattern will be very loosey-goosey and possibly too shapeless for use. If done on finer needles - more in keeping with the yarn you want to use, it'll probably be far too small for your intended recipient. If you don't have anyone you intend it for, go for it! At worst, it'll fit a doll, and you'll have learned something while dusting off your knitting skills.
As for using straights, unless the pattern specifies that it is knit in the round, or that there are umpteen-hundred stitches at some point in construction, use the straight needles.
Enjoy!
If you want to make a "a small child's cardigan" but are using yarn half the thickness ... the result done on the same size needles as in the pattern will be very loosey-goosey and possibly too shapeless for use. If done on finer needles - more in keeping with the yarn you want to use, it'll probably be far too small for your intended recipient. If you don't have anyone you intend it for, go for it! At worst, it'll fit a doll, and you'll have learned something while dusting off your knitting skills.
As for using straights, unless the pattern specifies that it is knit in the round, or that there are umpteen-hundred stitches at some point in construction, use the straight needles.
Enjoy!
Oops! I got confused and mixed up this topic with another one that's a crocheted top. It's obviously past my bedtime.
