Hi, NovaStar. I finally only recently got around to starting my Quartet Adventure, as well.
And I wondered the same thing about who to practice the speaking parts with.
… Seeing as we BOTH wondered the same thing within a week of each other, it makes sense that we team up as Study Buddies in this endeavor. I was gung ho my first week, but have since completely slacked off because I’m struggling mightily to keep up with the Advanced Book Club pace for 香君 at the moment…
… Anyway, here is a discord invite to the now-mostly-dead Japanese Study Server that I am a mod on… So we can meet in the (scroll down to Japanese Study and Help section…I use the Study Corner VC with the chat channel, Study Text 勉強チャット, where you can leave messages and comments any time, as well as in this thread)
Yes, I AM a discord RANDO! 
And for additional Ugh, too much! reading fun, I am copying (from my study log link) my Chapter 1 Quartet Study plan below:
QUARTET Ch.1 LESSON PLAN
Chap.1
.1. Day 1 Brush-up
…a. Book I p. 206-207 そうだ…みたいだ
…b. Book 1 p. 216-219 あげる/くれる/もらう
…c. p. 227-229 particles は が
…d. Quartet App 単語辞書 Lesson 1-1
…e. Quartet App 漢字辞書 Lesson 1 (1-23)/45
…g. Book p. 006-011 grammar
…h. Supp 単語リスト p. 002-003
…i. Supp 漢字リスト p. 028-030
.2. Day 2 読み物1
…a. Quartet App 単語Flash 1-1 (pretest)
…b. Quartet App 単語Q 1-1 (pretest)
…c. Quartet App 漢字辞書 Lesson 1 (24-45)/45
…d. Book 1 p. 002 読み前
…e. Supp 1 p. 002-003
…f. Reading p. 004
…g. 読んだ後で Book p. 002
…h. Book p. 012- 015 grammar
…I. OtoNavi Bunkei-Hyogen Bunkei_L1
.3. Day 3 読み物1
…a. Quartet App 漢字読みQ Lesson 1-1
…b. Quartet App 漢字書きQ Lesson 1 (pretest)
…c. OtoNavi Quartet 1 Yomimono 1-1 (no looking)
…d. Reading p. 004 Out loud
…e. Writing Book p. 016-017
…f. Conversation Book p. 018-022
…g. OtoNavi Kaiwa L1-1
.4. Day 4 読み物2
…a. 単語リスト p. 004-005
…b. 漢字リスト p. 00030-032
…a. Quartet App 単語辞書 Lesson 1-2
…b. Quartet App 漢字読みQ Lesson 1-2
…c. Quartet App 漢字書きQ Lesson 1-2
…d. Do 読み前 2 Book p. 003
…e. Read 読み物 2 p. 005
…f. Quartet App 単語Flash 1-2 (pretest)
…g. Quartet App 単語Q 1-2 (pretest)
…h. OtoNavi Nomimono 1-2
…i. Read out loud 読み物 2
…j. Do 読み後で p. 003
.5. Day 5
…a. Quartet App 単語Flash 1-1 and 1-2
…b. Quartet App 単語Q 1-1 and 1-2
…c. Quartet App 漢字読みQ 1-1 and 1-2
…d. Quartet App 読み書き Lesson 1
…e. Listen only to OtoNavi Yomimono 1
…f. Do ワクブクp. 009-010
…g. Re-read 読み物1 check ワクブクp. 009-010
…h. Listen only to OtoNavi Yomimono 2
…i. Do ワクブク p. 011-012
…j. Check ワクブク p. 011-012
…k. Do ワクブク p. 013-016
…l. Book 023-028
…m. OtoNavi Q1 Kaiwa L_1-2
.6. Day 6
…a. OtoNavi Chokai L1-1 with Book p. 029
…b. OtoNavi Chokai L1-2 with Book p. 030
…c. Review Supp 単語リスト p.002-005
…d. OtoNavi Q1 Tango L_1-1 and L_1-2
…e. Review Supp 漢字リスト p. 028-032
.7. Day 7
…a. Take the test ワクブク p. 017-020
…b. Quartet App ふくしゅう Lesson 1
…c. 単語Flash 1-1 and 1-2
…d. 単語Q 1-1 and 1-2
…e. 漢字読みQ 1-1 and 1-2
…f. 漢字書きQ Lesson 1
I will add that, regarding my lesson plan: in practice, it was better to just bash through and read Reading 2 (for me, a few days) after Reading 1 (and related vocabulary, and pre-studying the Reading 2 Vocabulary), because the entire remainder of the chapter expected both readings to have already been done, and then diverged significantly to other topics…
I’ve just been copying it, and adding checkmark as I go, to show what I’ve completed.
I had written out my own set of grammar notes to try to quiz myself on how to achieve the (9? or so) grammar points discussed on that chapter, but I’m not functionally recalling them at all!
EDIT (After going back through and reading old posts): Wow! I really like how our thread host made the Textbook and Workbook sections into a vote-able Checklist! Great idea!
Probably the lack of grammar recall on the last check is what slammed the brakes on for me with this project… 
It seems like @pandoravakarian also started Quartet at the same time, so we might have a third Party Member on this Adventure? Perhaps a 4th with @shitsurei さん?
The More, The Merrier©
It seems that I have missed all over 100 posts on this thread, so I will have to take some time to scroll up and scan. “Later” 