How do I change the size of the chart so that one column is longer then others?

You can use the custom CSS code below to adjust the width of each column. Here's the code:

/* 1st Column */
.form-matrix-row-headers +
.form-matrix-values .form-textbox {
width: 100px !important;
}

/* 2nd Column */
.form-matrix-row-headers +
.form-matrix-values +
.form-matrix-values .form-textbox {
width: 100px !important;
}

/* 3rd Column */
.form-matrix-row-headers +
.form-matrix-values +
.form-matrix-values +
.form-matrix-values .form-textbox {
width: 100px !important;
}

/* 4th Column */
.form-matrix-row-headers +
.form-matrix-values +
.form-matrix-values +
.form-matrix-values +
.form-matrix-values .form-textbox {
width: 100px !important;
}

/* 5th Column */
.form-matrix-row-headers +
.form-matrix-values +
.form-matrix-values +
.form-matrix-values +
.form-matrix-values +
.form-matrix-values .form-textbox {
width: 100px !important;
}

Here's a guide on how to inject custom CSS. Please take note that you can change the 100px width if you wanted to. Here's the result:

Hope that helps. Thank you.

Thanks. I need to add drop down options for Strength and ring size column?

...

Unfortunately, it is not possible to use different input type for different rows/columns of an Input table field. If you want the other columns to have a different input type, it is required to use a separate input table field on the form.

Hope this information helps!