Yeah my friend plays on playstation and prefers to use one multi-tool because not as easy to switch. I use ctrl+1 and ctrl+2 to switch, which is a breeze.Not super easy have to go into the menu to switch multi tools, will look for a rifle, currently using a pistol as both.
Ship is a class B so not super great, but on finding it they did give me blueprints for some underwater base stuff, I mined gold for quite a bit in the beginning to get units, so had around 7 million for awhile, I'll attempt that one tonight for killing quadrupeds.
The base is on a floating island, with a small waterfall going into a stream which than becomes a waterfall onto another floating island just below it. I thought you couldn't build bases close to others, guess not.
If you haven't already, you can scrap any additional ships you have for extra money but sounds like you have enough. I used the paralysis mortar for the quadrupeds but you do need a fair stock of unstable plasma if you use it as much as I do! You may well have a different secondary weapon you prefer.
I haven't tried to build a base on the floating islands, must try that in my main save, maybe even build across a few if they are close enough. I also thought you couldn't build close by but maybe your settings allow others to change your base and they added on to it? Otherwise sometimes things glitch a bit in multiplayer.



. Definitely fancier than my basic timber structure!
