Yarn substitution

Hello all,
I am hoping a more experienced knitter than I can give me advice on a yarn substitution. I want to knit the Shibui Mix No. 1 sweater. The pattern calls for two Shibui yarns held together, and while they are beautiful yarns this is my first sweater and I don’t want to spend that much on yarn. But I’ve looked at hundreds of patterns and I really like the cut and style of this one. So I am thinking I can use a different, single yarn, as long as I gauge it correctly, right?
The yarns they use are a worsted weight and a lace weight held together and the gauge is 14 st/ 4 inches. So is it safe to say that I should be able to use a slightly thicker single yarn, like bulky i guess, and maybe adjust needle size to achieve 14 st/ 4 inches?

Yes, a bulky on needle sizes ~9-11 should work for 14sts/4". See how the gauge swatch goes and whether you like the drape of the knit fabric.

Even a thicker worsted ought to get that gauge on a size 10½/6.5mm needle, but a bulky would work too.

So, as long as the swatch gauges right and I like the resulting fabric, I shouldn’t worry about using a totally different yarn? The result will be sort of a version of the same in different fabric? That’s great, very helpful.
Thank you both!

The only other thing to keep in mind is that when you use a yarn that is different it may affect the way the fabric looks. I rarely use the suggested yarn and I usually like it just fine and sometimes more. You’re gauge swatch will give you an example.

I never seem to use the yarn suggested for the pattern. I have found that a springier, stretchier yarn can affect the fit and I often should use a smaller size to allow for needing less ease in the garment. This I’ve learned the hard way and understand why a little better because ArtLady explained it in another thread…I’d link to it but I don’t recall which one it was.

Also very useful advice, thank you. Is it accurate that if I sub merino for silk that would, in fact, be a springier, stretchier yarn?

I don’t know. I’ve never used merino or silk, I mostly use acrylic yarns.

Make a good sized gauge swatch (at least 4x4 inches), measure it, then wash it how you’ll be washing the garment and then remeasure. That should give you an idea how the fabric will look, how it handles washing, and if it stretches or shrinks. Some wools do stretch when washed and blocked. There is still no guarantee it’ll all work out, but it’s a start.

Yes, the merino is going to be springier than the silk which tends to have less give. The silk may have more shine to it though or be blended with other yarns to give it more resilience.