You can always submit your measurement after placing the order. For now, just select Customize with Made to Measure, click Add to Shopping Bag and complete order. Later on go to Account section, visit My Orders page and submit your latest measurement.
If your bare chest size measurement is 40 inches, you should select size 40 only from the product page. The "Top Chest" attribute in the size chart refers to the garment's chest size. It is inclusive of the required 3 to 4 inches loosening, to ensure the right fit.
If your bare chest measurement falls between 2 sizes i.e 37 inches, you should select size 38.
https://www.utsavfashion.com/product/crushed-art-silk-stole-in-black-mse652310258Crushed Art Silk Mens Stole in Blackhttps://medias.utsavfashion.com/media/catalog/product/cache/1/small_image/295x/040ec09b1e35df139433887a97daa66f/m/s/mse652_2.jpg17.622USDInStock/men/men/festive/men/art silk/men/black/men/dupattas/men/traditional/men/zariCrushed Art Silk Mens Stole in Black <ul><li> This zari woven piece is enhanced with tassels</li><li> Do Note: Top and Bottom shown in image is for presentation purpose only</li></ul>USDadd-to-carttype_new:Dupattascolorfam:Blackfabric:Art SilkBlackArt SilkDupattas11%-20%MenReady to Ship, Within 2 days, Within 7 days, Within 10 days, Within 15 days, More than 15 DaysReadymadeFestiveMenswearTraditional, Zari