New guy, old boat, dead transom

[Austinboat]

Some help. I'm new on the site. Recently acquired an 88 WA 23, transom is definitely in need of replacement. Has anyone any experience with solid glass transom. Know what the advantages would be but what would be the disadvantages? (Too heavy, too inflexible?)Plan to bolt on a floatation bracket after transom repair and remotor with 250 yamaha hpdi. Have access to lots of kevlar, 6 oz felt and heavy cloth and was thinking of building solid transom but I never see that listed as an option. I know there must be a reason, someone enlighten me.