Welcome to modular and let's not spoil time and let me straight get to the points ;-)
That 4ms module, nice one for sure, but at 26 HP, that is more than 15% of your rack space, that's more than one seventh of your entire space, so seven of these kind of modules and your rack is full mate! Then we didn't talk about the finance yet, this module hits the 500 bucks marker line, yet another thing to consider: "Should I really start with a rack and with a module like that?" Up to you of course, but if I were you, I would reconsider it.
Your rack is (far) too small, if you would ask me, see my above explanation of the 15+% usage of just one module... and you should keep some space reserved for future needs.
Another large module is the Maths module, I know it's a great module, everyone can recommend it to you, including myself, but at 20 HP size (12%) you should ask yourself the question: "Do I need this module, or am I going to use it for EG functionally only in the beginning?" If you indeed only going to use it for its EG capabilities, then you might want to consider just a dual or quad EG module, much smaller, and most likely cheaper than the Maths too. Unless of course you are very sure of your Maths usage that you will full utilise it, but with a relatively small rack like this one that's going to be a serious challenge.
So, 27% gone of the space with just these two modules ;-) That's already more than a quarter of the total rack space... hence you need more rack space (even without these two modules).
And I can continue this story but I guess you get my point by now ;-) I am not saying those modules are bad, no not at all, they are good in their ways but to start with and then in such small rack, as already mentioned, you might want to reconsider some of those larger modules.
So my advice is to reduce a bit on the "fancy" (or complex) modules and start with a bit easier ones, smaller ones, basic ones and cheaper ones, that might save yourself a few surprises.
Going completely back to the basics, how familiar are you with synthesizers? Are VCOs, EGs, VCFs, VCAs, LFOs and that kind of "phrases" known to you? If not, you might want to go one step backwards and consider a Behringer Neutron for example to start with. It's a cheap semi-modular way to get started and gives you a first kind of taste to modular if you are really want to go into modular. If not, then everything fine, sell the Neutron and you haven't lost much. If yes, then you are ready for it because by then you will know it :-)
Don't get me wrong here, if you are sure about yourself and modular, then go for it I don't want you to think that modular sucks (it doesn't), but it might need a bit more investigation, checking, tons of reading and clarifying things, get to understand each of those basic modular concepts, once done that, go ahead and welcome to modular.
Before that though, be careful, read & check and plan carefully. Modular can be (extremely) expensive and if it's not your thing after all, then some serious bucks went down the drain and that would be pity beside the fact of disappointment.
By the way, regarding your rack, look into filters, a mixer and an audio (input/) output interface on top of what I already recommend to check.
Anyway, feel free to ask around and welcome to modulargrid, kind regards, Garfield Modular.