noob questions about scopes [getting one soon]

[prawncrackers]

hello guys, a fan of dave's youtube stuff here! decided to join the mob 


ive been an electronics enthusiast for a long time now. i saved up my allowance and i can now afford an entry level scope and looking at the Hantek DSO5102p at USD244 from Aliexpress please note that its all i can afford and i have a small customs tax to worry about. i have a few questions to ask before dropping my savings hehehe...

1. so i was thinking id ask around here (more like to confirm), that theres nothing better than this scope at this price?

looking at the datasheet http://www.hantek.com/Product/Datasheet/DSO5000P_Datasheet.pdf it says the max input voltage with 1x probe is 150vrms(300vrms with 10x) regardless of software coupling, our mains is 220vacrms and oftentimes i work with my friends tube guitar amps with voltages reaching 450-500vdc

2. so if i forget to toggle the 10x in the probe does this mean id instantly fry my "expensive" scope? this seems silly but i admit i make mistakes of sublime stupidity. my DMM has higher max voltage headroom so im not that worried.

 im thinking since i may not be able to afford a 100x probe soon, im thinking of making an L-pad attenuator/adapter (F-M BNC) from 1% MF resistors 9.9M + 100k (im even thinking of lower impedances like 990k+10k) for measuring high voltages. capacitance isnt really important for my HV purposes.

3. is it a good practice to "permanently" have this adapter on and remove only when i need precision low-ish voltage scoping?

4. i may be a bit paranoid but i think ill open it up and put sort of protection like a 200v DIAC or zener or the typical clamp diodes (ground to signal to vcc) but wont their capacitances affect measurement?

5. ive seen dave's video on how not to blow up your scope. shorting voltages across the probe negative clamps through the bnc grounds, yeah, thats something i can see myself doing. is it possible or a good idea to put a fusible resistor or a ceramic fuse between the BNC grounds and its PCB connection?

thanks for taking time to read my questions. it may not be much but im excited getting a scope and a frying scope isnt really a nice feeling and an exploding probe might trigger something inside the heads of my parents.