Disclaimer,. I have not built a "cottage studio". I am however in the process of sorting out my bedroom studio,. with hopes of moving into a larger space(large garage basement(apx. 20'x25') in the next couple of years. Based on the homework I've done I can see a couple of issues with this design, some of which maybe viewed as "opinion".
First off it really looks like the the whole thing has been repurposed rather than built to purpose
The control room is to small, and to face the window your mixposition must be placed around where the first "o" in the word control is in the drawing. That puts you about 2.5' back facing the longer wall leaving only 4.5' behind you,. I can imagine the end room layout and it seems constrained, and that seems like a small issue compared to the likely room mode issues your likely to occur. From a small room acoustics stand poind you want to be seated facing the short wall,. Then your sound treatment options become more practical and predictable.
Room 1 looks servicable, but again , bigger is better,.
Wheres the bathroom?
Why an entrance/office for a home studio,. waste of space.
All in all i'd rather have the majority of the space open with maybe a small bathroom and 1 iso booth. Might take more time to get everything miked up since without a control room you'll end up doing more test recordings, but you'll make up for that lost time by :
A: being able to leave some things setup permanantly, like drums, so that they become controls rather than variables in your mix process.
B: The improved room acoustics from a larger, properly treated room will mix much faster/easier than the alternative.
Read these before you spend your money and good luck whatever you do.
https://homerecording.com/bbs/gener...oustic-treatment/small-room-acoustics-365127/
Acoustic Treatment and Design for Recording Studios and Listening Rooms