Anyone have any thoughts on the topic of fiberglass vs aluminum drift boats? I'm trying to decide between a 17' Clackacraft and a Willie: I notice that most of the guides run alumium boats. (Does Clackacraft's tunnel hull system actually make a difference?) Also, do any of you have experience with the larger driftboats, up to 20 feet? (I'm not a guide, and was wondering if the extra space of the longer boats is worth the extra rowing effort, assuming that there is more rowing effort required). Thanks.