Quick question -- can you easily convert back and forth from AR and "retro" magwells or is it a permanent commitment w/ the hole drilling? My concern w/ the original mags is that with there being more than a few Scorpion Evo mags cracking even just sitting new on shelf unloaded, presumably these are of the same polymer composition...
The lancer translucent mags are neat and probably most appropriate considering the original, but generally you can save 25-40% per mag by going w/ the opaque version... Opaque versions of polymer generally also have proven to be more durable in torture testing... With mag inserted into an AR magwell, you can only see the bottom ~1/2 or 15-18 rounds or so anyways.
Botach has one of the better deals on Lancer mags, especially when accounting for free shipping and no tax if not in CA; 43 translucent smoke lancers in stock right now:
https://www.botach.com/lancer-l5awm-5-56mm-magazines/Translucent smoke @ 1-2 mags, per mag: $21.95
Translucent smoke @ 3+, per mag (10% discount): $19.76
Translucent smoke @ 7+, per mag (15% discount): $18.66
Opaque @ 1-2 mags, per mag: $15.95
Opaque @ 3+, per mag (10% discount): $14.36
Opaque @ 7+, per mag (15% discount): $13.56
You can combine multiple colors, including translucent and opaque, to reach the discount quantities.
Sportsmansguide has 3 mag package deals on opaque lancers too that aren't too bad of a deal if part of their buyers club and taking advantage of a free shipping promo...
Cheaper at botach are HK Smoke Translucent Stanag mags @ $15, no quantity discounts:
https://www.botach.com/heckler-koch-hk-5-56mm-polymer-30rd-translucent-magazines/Or
ETS Smoke Translucent @ $15 per 1-3, 4-6 @ $14 per, and 7+ @ $13 per:
https://www.botach.com/ets-ar15-m4-translucent-5-56mm-30rd-magazines/Main thing w/ ETS is they have a coupler option which allows you to link two mags together:
http://www.defensereview.com/elite-tactical-systems-ets-ar-mags-coupling-capable-all-polymer-smoke-translucent-5-56mm-ar-15-rifle-magazines/Don't have personal experience w/ either of these mags, but have seen really good reviews of ETS and what I've seen on HK have been sort of meh. Also, both have thicker lowers than upper, so PMAG gen 3 reviews are probably a good guide for what weapons they'll fit.