I'm brand new to the forum and the tea community in general. I am really enjoying Japanese Green teas at the moment and have the bug to get a tetsubin. I've looked through a lot of threads here and researched as much as I can online but couldn't find much in the way of sizing recommendations. I'm a little hesitant to apply my version of common sense to this issue as it did me a disservice when selecting a kyusu which is probably way too big. That, and well, my common sense is not really the common version anyway

My questions are derived from me being torn on whether to purchase a 1.4L and 0.9L tetsubin from Artistic Nippon. The 0.9L is available for immediate purchase at what seems to be a good price and well within my budget at $290 not including shipping. The 1.4L must be special ordered as it is not in stock and will take 3 or more months to receive. It is a bit more pricey at $380 not including shipping. Anything else listed in stock is getting outside my budget at well over $400 but not completely out of the question.
So in considering this, the smaller Teppachigata arare by Kunzan 0.9L seems like a better fit for my budget but I am worried that it might be too small. Then again, I am usually preparing Japanese Green tea for one on most days so maybe this would be perfect? Do you think the smaller size would better for day to day use for a 1 to 2 person kettle?
Or should I wait for a larger tetsubin which may have more versatility if I am to serve larger audiences during holiday get-togethers? Is the larger one more challenging to use during the smaller tea drinking sessions, which will comprise the majority of its use? I am currently using a 1.2L stainless steel kettle and it seems to work well. + or - a few mL doesn't seem like a big deal overall but I am guessing those that have gone before me can impart much wisdom on this consideration. Many thanks in advance for your help!