Recommend you seek quotes from 'Stone Vos,' 'Tough Tops' and 'Carefree of Colorado' - well-known companies who provide quality materials and instructions. Search internet by name. I don't recommend you contact WBGO directly - they buy their products from Carefree (on most rigs) so may not offer the best price.
And - ensure the thread used is resistant to sun and moisture - not the cotton often present on OEM covers.
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Steve
2015 Itasca Ellipse QD | 2014 Jeep Grand Cherokee