Dan, leave the trim and forget the vinyl top idea. Your car looks good as it is. You already have a '74 probably like not other, the trim just adds to that exclusivity.
If it ain't broke, don't fix it. Your car looks great, Dan. Maybe do the black Grabber stripe on the hood (it will go nicely with the black-out taillight panel)...
Dan, if you decide to weld up the side trim holes, also consider the Maverick emblem on the top of each quarter panel. I welded up the ones on my '73. I think it cleans up the lines. I always thought it looked out of place there and it seems to collect a lot of dirt and wax.
One thing is certain...if you post this question here, a majority will tell you "Don't do it, vinyl tops suck". I didn't even have to look in here to know you would be strongly advised against doing this. Just like if you asked if you should keep or add power steering many people here would say "chuck it!". Similar responses would be found for power brakes(although I think I have seen more people who like P/B...a strong sentiment I have seen is "the car is so light, you don't need them..kinda like the steering.) My point is that sometimes you gotta do what you like in spite of what the group thinks. My car has all of these things and a lot more. Most times people won't tell you they don't like something about your car to your face, although I have gotten an online comment or two ripping something I have done to my car..and it does sting a bit because it hits close to something that is important to me...but on the other hand I have been stopped in parking lots and waved at on the road and at stop lights more times than I can count with people who seem to really like my car. Either way, I like my car, so F- the rest... My opinion? I happen to like black vinyl tops and I agree with your second post, that vinyl tops do look kinda classy. In particular, I like the look of a dark colored top on a lighter colored car, and I think it could look good on your car. By the way, mine came with a vinyl top and the grabber hood and stripes from the factory, so it is not like it is completely non-standard. Anyway, think about it while and if you think it would please you every time you glance at your car in the driveway, be the ultimate Maverick, buck the majority and go for it!
Dan, with the colour of the car, the hood, wheels and tires your car has the "sleeper" muscle car look. If your car was white with a regular hood and had white walls, I vinyl top would be fit in. The bottom line is you have to do what you feel is right for you as you will be stuck looking at it and driving it.
I think the big bumpered Mavericks look better with viynl top and side trim....so convert it to a big bumper car.