(This includes manifest, disguise, cloak, morph, and a few older effects that turn cards face down.) Common methods for doing this include using markers or dice, or simply placing them in order on the battlefield
Bell Borca, Spectral Sergeant and Umbris, Fear Manifest are secondary options that become substantial threats as we exile more and more of our opponents cards
What Pokmon cards are a good investment
An MTG cards length is 2.5, its width (i.e., thickness) is 0.012, and its height is 3.5
The only major downside I can see here is that its pretty easy to interact with Jecht before you transform it, but thats about it
A green/white deck or a green/white/black deck should have plenty of single-target cards to help Legolas get +1/+1 counters or open fire, such as Shelob's Ambush, Morgul Knife-Wound, Bitter Downfall, Second Breakfast and Gollum's Bite