I am going to skip around here:
#2. The cheapest way to get a dry glove system with your current setup and no modification to your suit. Buy cheap rubber pull over gloves like this:
Super Grip Black Dry Glove
Then order this:
Dry Adhesive Drysuit Latex Wrist Seals
Put the two together and you have close to what you are looking for (not the exact glove but same system of attachment) Total $46.
You could use glue instead of the tape there is really no difference. The tape works well.
#3. Do the same as above with glue ($12), buying just the seals without the tape. Making the total ~$51
#1. Unfortunately I do not believe the Nitrile 720's will glue to a latex seal. I could be wrong, but I doubt it. They will only seal with a ring system installed. This is due to the fact that they have a liner built in that would prevent sealing without folding the gloves over on themselves.
The real hiccup in the whole process is the neoprene seals currently on your suit. I understand the hesitancy of wanting to replace what is perfectly fine. But, follow along with me for a second. Here is an idea you have not thought of. Take a heat gun to your current seal/suit. Remove the existing wrist seals. Then use Aquaseal (without the cotol accelerate) to glue latex seals on. *or a Si tech oval ring. This would allow you the option to then use a ring system with the 720's. It sounds like a lot but the most expensive part is the ring system. The ultima goes for like $170. If you added an oval cuff ring to the suit that would add an additional $69. But isn't exactly necessary. You could still mount the ultima system to a plain latex seal.
Run down:
Ultima rings ~$170
Latex seals ~$25
Aqualseal ~$12
720's ~$free if you call them
Oval rings ~$69 but not needed
The reason I am recommending you use Aquaseal over glue is the cure time. It allows you to glue without worrying about making a mistake. The cure time is like 12 hours. So you can glue the suit and the seal and press them together, if your alignment isn't correct you can fix it without having to start over again. Using the glue isn't difficult but does not leave much room for error. Once the two pieces contact each other that is it. If the alignment isn't good you have to start over. A trick to this would be to use a cut up piece of ziplock bag in between the seal and suit until alignment is perfect then remove the ziplock.
Unfortunately this is the reality of having the neoprene seals with the smooth side inwards. You could also try the dry 5 gloves, I know they are neoprene but they might fit your need. They have a built in cuff (not a full latex seal) that slows the migration of water, keeping your hands warmer. I was in a similar situation as you are about 3 years ago but with a trilam suit that had latex seals. After many different attempts I settled on the ultima rings, 720's. I wish I had just done it in the beginning, I would have saved a lot of $$ and aggravation. Kind of a buy once cry once sort of thing.
There are endless combinations that I could think of. What I said above isn't the bible. I am just speaking on experience.
