Let's just slip it on for size.

（ためしにちょっと着てみて？）
ディズニー映画「シンデレラ」より。新入りのネズミにお手製の洋服を持ってきたシンデレラ。新入りネズミはちょっとぽっちゃりさんだったので、こういいながら服を着せる。

• 「試着する」を「try on」というけれど、そこに「サイズを確かめたいので試しに着てみたい」という気持ちを込めるなら for size をつければいいのか、と。
• この場合のsizeは実際の寸法を表すだけでなく、アイデアなどがfitするかどうか、という捉え方もするみたい。try something (on) for sizeで "to test something or to think about an idea in order to decide whether it works or whether you can use it. "とか"to test something so you can form an opinion about it. "とのこと。
  • Try that for size. It's the new software programme I've been working on.
  • The government is still trying some ideas on for size before committing itself to action. --I don't think everyone would be happy working here, but you should try it on for size and see if it's right for you.
  • The company is going to try flex-time on for size in the Personnel section before adopting the policy company-wide.