There is quite a few philosophies out there concerning guides, regarding: size and size progression, number, placement from tip, placement at ferrules, distance from grip, etc.
And most builders typically formulate their own strong preferences through mimicking rods built by others that they enjoy, trial and error, advice from forums <wink>, etc.
I honestly don't think that any of these subtle variations (within reason) makes an appreciable difference to a blank,
but psychologically, there will be some choices that just seem "right" to you.
A maker I respect once wrote to me about the affect of these assembly decisions:
"95%+ of the action is baked in (to the blank) -- us assemblers are only tinkering at the margins."
I'll offer my own opinions:
for Strippers: on short 3/4 wts. #7 or #8. #9 is my favorite for 5/6 wts. #10 is the largest I'll ever use - reserved for long 6/7wts. (I don't flyfish with lines heavier than 7wt. as of yet ... )
for Snakes: I follow a #7 or #8 stripper with a #2, progressing down to #2/0 or #1/0, I follow a #9 or #10 stripper with a #3, progressing down to #1/0 or #1.
"Quick" size progression
I drop a size in snakes with each successive one from the stripper until I reach my smallest, and use that size for the remaining guides up to the tip top.
Lots of guides
Most modern builders outfit their rods with Length + 1 (8' rod would have 9 guides), but I almost always find that Length + 2 is better (8' rod would have 10 guides). Might be because I build a lot of slower blanks, and thus they bend more along their length? But I always static-load test to arrive at number and spacing.
This is also due to my preference for the guide placement of the stripper closer to hand, and last snake closer to tip than most builders use - so I've got a bit longer "effective length" to fill.
My advice is to filter information like this from a lot of different sources, and then tape-on some guides to a blank and start experimenting. test-cast, static-load test, test, test, test. Eventually, you'll find what you like.