If you've never worked with acrylic before, you should definitely do some practice joins before you do your final project, as working with Weldon #3 is the best, but also the hardest to get a good finish and seal if you're not familiar with acrylic joining techniques. Brian Ferguson is teaching a class on acrylic joining techniques through #reefs I believe, you might want to check some of the archivers there as well for some good tips on these techniques.