Would I be better off doing another Eclipse kit and then reusing the skins? Could I reuse merlot skins for a Cabernet?
As Cmason said- just skins won't do what your looking for it to do. Plus a grape lug to go along wouldn't need equipment- just a 2x4 and a bucket!
And it's fun to change the varietal to make a cool blend. For a cab or a merlot pail (some sell a cab/merlot mixed pail) you could get a ton of diff grapes and have it work well. Syrah, Sangiovese, or merlot or Cab for a Tuscan/chianti style. Or "Bordeaux-ish" go Cab Franc, Malbec, Petit Verdot, or carmenere. And even tempernillo maybe ------- I digress.
just keep in mind you end up with a funky sized 8 gal batch
I did a cab from grapes a week before a juice pail with the skins added to the juice pail primary. Plus about 10 lbs of actual grapes added. The juice pail is coming along very good. And I'm very happy with it. But the grape batch is still noticeably better. All that to say if Choosing skins or grapes--go grapes if you can.
Or just do a straight juice pail. I know they get mixed reviews on here but the best wine i've made to date was from juice (my grape wines aren't bottled yet) . And with nothing added at all. Just yeast. At 1 yr it was pretty good and was gone by 1.5 yrs. But then I found a straggler bottle aged over three years at that point and it was freaking incredible. I couldn't believe how well it aged. Better than any other juice batch or kit I've done. (Cab Sav Regina Juice bucket)
I've seen people whove just done kits be hesitant to "move up" to juice pails, but I think it should be the opposite. Juice pails are easy peasy compared to kits. No degassing or agents or confusing instructions. And can be as simple as yeast, k-meta and Father Time. And can make some damn good wine.
As far as your original question I have been using this additive pack and I love it. And only $5. It's all prepackaged for a 6 gal batch. And then I'd just add an oak spiral during bulk as needed.
https://morewinemaking.com/products/additive-pack-brehm-frozen-fruit-reds.html