You can get a little gain by tinkering the spring, but I'm not sure it's worth it. The width of the pawl and gear is also a limiting factor as to available resistance. If I remember correctly, your Trophy model has dual arms/pawls and can be used with both engaged, at the expense of a little more winding effort and perhaps a bit more wear. I'd try that first if you want more drag. My inclination would be to use it for what it is with light drag to prevent overrun as you described.
For more outgoing resistance in a robust adjustable click--that's the JW Young series reels over many years, right back to the reels from the pre-palming rim era as suggested above.coming forward, though, they phased in palming rims on various models, culminating in the excellent 1500 series of the early '80s, branded for many others as well, including Shakespeare, Daiwa, LL Bean, and Sage. They came in large capacity models both by spool width (I think that's the 1530) and then, for even more, a salmon model of larger diameter. Various ones retained the "Beau-----" nomenclature, and some came with a different adjuster mechanism. Since it's right handy, for example, see
http://cgi.ebay.com/ws/ebayISAPI.dll?ViewItem&item=150402972778&ssPageName=STRK:MEWAX:ITReels in this series had gear and leaf springs more robust than the rear end of a Vauxhall. Search Young 1500 series and the various "Beau" names here and you'll find a lot on these reels.