I read that the Ramchal published the Mesilas Yesharim but not too many other books. That got me wondering, how many and which books that we have of his did he himself publish and which ones did someone else publish (most likely after he passed away, I assume)?
In R Yirmeyahu Bindman's biography of the Ramchal (from 1995), he writes indeed that
Most of the Ramchal's works were not published in his lifetime but circulated in manuscript or small, privately printed editions. [...] Manuscript material that remains unpublished has recently been gathered together [...] but some items are still uncompiled.
He then lists the year of the first full printed edition intended for general readership (but mentions these are only titles of more general interest - note that Wiki's partial bibliography has 42 titles).
From there the following titles were published during the life of the Ramchal (1707-1746)
- Shir Zahav Lichvod Concili, Venice, 1723
- Lashon Limudim, Mantua, 1727 (Mantua is a day trip from Venice by horse)
- Shir Chanukat ha-Aron, Venice, 1729
- Shir al-Mos R. Binyamin Cohen Vitali, Venice, 1730
- Mesillat Yesharim, Amsterdam, 1740
- Derech Tevunot, Amsterdam, 1742
- Layesharim Tehillah, Amsterdam, 1743
The dates and places are consistent with the Ramchal's move from Italy to Amsterdam, leaving in Heshvan 1734 (Wikipedia says 1735 but that is when he arrived).