Which "should be" on fuse block and which should be inline? makes no difference. Try to do all in fuse block. If not, add an inline. Normally inline's are used in old trucks as an "add on" safety or added component. You are starting from scratch, so all in one box is a good goal.
You will use fusible links for the main hot feeds to fuse box, ignition switch, headlight switch, foot start. (not sure about 1949 system). Basically a fusible linked hot wire from battery positive to ignition switch, then ignition switch to hot bar on fuse panel. That energizes one side of fuse contacts when ignition is on. The other sides of fuse holder contacts go to various switches and components. Some components could have their own fuse ( I.E. radio, headlight switch). You may want some circuits to be hot all the time and not be turned on by ignition switch. That would be a fusible linked wire direct to a separate section of fuse hot bar.
As said, everything needs fused or fusible link. You can buy a donor fuse box from any vehicle that has the size you need and quantity of circuits or a new box. The mini fuse/ATO box will be the smallest. Don't let "hiding" the box control your life. Just mount it in a practical place for wiring and access. you are updating as per normal people, you are not building a museum piece.
Fusible links are just a special wire, sized to be four wire sizes smaller than the wire they are protecting. Like 16 ga fusible link protects a 12 ga wire. Available at all the FLAPS. Place them at the battery end of a hot wire.
