Given you're based in Texas, IMHO the main thing you need to focus on regarding your engine bay is ensuring you have all the tinware needed to direct cooling air over your cylinder heads. @DannyP's comment about the dogsled tins is something you need to read up on, as is the isolation between the engine bay (cool air intake) and underneath (hot cylinder heads needing cooling). It's not difficult to sort the tinware even for a custom build and there are multiple ways of skinning the proverbial cat.
I personally don't think you have to be completely anal about every 1mm hole (although it never hurts to be detail-oriented, eh Danny?), but if you do get the engine bay sealed AND run a remote oil cooler you should be fine even if the weather is: