Hi, I think the Sustain was a great reel & of the two the 10k would be the better option depending on the rod your gonna put it on. As for either doubling as an option for Marlin I think that might be a bit optimistic.
Which ever reel you go with the rod & braid will all need to match up, no point having a small reel on a monster rod or Vis versa.
Hope that helps & good luck.

Varivas casting if the budget allows it

Hi Andre, the sustain would be a fine reel to start out stickbaiting with, the saragosa 10k might be worth a look too if you are wanting to go shimano, generally cheaper as well what ive seen.

Size wise is going to depend alot on what size fish you are going to target, and what size lures you are going to want to cast, do you have a rod in mind that you are going to match it to? if your wanting to cast large stickbaits & poppers a heavier rod is going to be needed and vice versa for the lighter-medium lures, i would then base the reel size off of this.

Feel free to PM me with any questions / if you want to have a chat im always looking to meet new people that are into/getting into topwater fishing/casting, im no expert or anything but have owned & own a few different setups and try to get out for a cast whenever i can.
Cheers.

Would have to agree & disagree on that Tony, not that you don't know what your talking about (you have alot more fishing experience than i do lol) have followed your work for a few years , and maybe will get to fish with you one day, currently looking at doing the GBR with Nomad at the moment so maybe after that.

True the 8000 has a higher gear ratio, but the 10,000 has a larger spool which intern means there isn't a huge amount of difference in the rate of line retrieve, both between 100-105cm(the 8000 a couple of cms more) which would make either one ample for casting & retrieving stickbaits.

Also the 10,000 is 'suppose' to make a bit more drag(2.5-3kg) more, but then also weighs a bit more which can be a deciding factor.

If i was starting out again now and had the choice between these two reels i would actually go with the smaller & lighter of the two(8000) like Tony has said, as a nice light balanced setup is so much more enjoyable to fish with/cast all day.

I run both a heavy PE8 setup & a lighter PE3 setup for kingis so can see the merrits in the 6000-8000 size (shimano sizing)reels when casting all day.

My 2cents worth

Yeah nothing wrong with those t curves, with the braid i would be looking at getting a minimum of 200-250mtrs on the reel which wont be hard, also alot of braids out there break at alot higher than stated on the packet (powerpro, suffix 832, jerry brown break at 15lbs or more than stated) while some break pretty close to stated, so would look at actual breaking strain vs diameter.

http://www.paulusjustfishing.com/4linetesting.htm
this chart on the site above may be helpful, money no object the varivas & YGK casting braids are great, but like double the price of anything else. I have had a good run from suffix 832 in the lime green, and is available everywhere for $60-70 retail for 300mtrs,if you went 40lb would break at around 60lbs, and 50lb would break at over 70lbs, theres only 0.1mm difference in diamter and the 50lbs tends to be more commonly stocked so might be more the go.

Sorry for the long winded comments, hope this helps though.
Cheers.

Yeah forgot to mention the ocea braid, is also meant to be pretty good from what ive heard, know guys using the PE8 121 lb on big GT's in aus and they love it, is getting more into the relm of varivas or YGK pricing though, i just wouldnt buy into the shimano marketing that is anything new or stronger when talking comparing braids of the same diameter vs actual breaking strain.

Even plain old powerpro in say PE8 '80lb' breaks at over 110lb(although not as nice to tie/cast as supple), and as i said above the suffix PE4 '40lb' actually breaks at over 65lbs when tested.

I think it is more just smart marketing on shimanos part to state the actual breaking strain, i know varivas do the same on some of their braid too.
Plenty of good options though these days compared to a few years ago.