While I think the occasional Foundry Elizabethan Sea Dog might work (as a more fashionably dressed, "modernist" among Grace's men, or a Spainard or renegade Englishman), don't forget that the bulk of her men are 16th century Irishmen (and some Scots), and most of them would be dressed like other Irishmen of the period. The Wikipedia article notes that she recruited mercenaries from both Ireland and Scotland, including gallowglass mercenaries (and her second husband wore a mail shirt). In addition to the Foundry range (which really make better opponents for her, then troops for her), Sgt Major Miniatures carries a range of 28mm Elizabethans that includes Irish kerns and gallowglass (as well as Irishmen carrying calivers, but dressed in more traditional garb). I use his Scots and English borderers to supplement my (more expensive) Foundry Elizabethans.
They are also useful to make up Tyrone's army, for leading Elizabeth's troops a merry chase through the bogs.
http://www.sgmm.biz/Irish_c_71.html